Inspirations: The Lie of the Land

Not a great deal to say about this one, as we've covered a lot of the background already.

The final part of the Monks trilogy originated with Toby Whithouse's idea for a story based on the sort of totalitarian society seen in George Orwell's 1984. The writer then had to make this act as a sequel, and conclusion, to the previous episodes.

Steven Moffat liked the idea of an invasion that had already taken place - and the Doctor appearing to be collaborating with the invaders. As the darkest iteration of the Time Lord to date, viewers might actually believe that he really had gone over to them.

His role appears to be inspired by Nazi propagandist "Lord Haw-Haw" - William Joyce - whose "Germany Calling..." broadcasts to Britain during WWII were designed to sap morale. He was the inspiration for the villain in Sherlock Holmes and the Voice of Terror (1942). Joyce was hanged for treason in January 1946.

The Doctor appearing to be undergoing a regeneration, but not actually going through with it, had been seen in the cliffhanger to The Stolen Earth, and the Eleventh Doctor had undergone a non-regeneration in The Impossible Astronaut. In the former case, he did use up a life and had to redirect the regeneration energy into a compatible organic receptacle (his hand), whilst in the case of the latter incident it was only a robot copy of the Doctor.

The main element taken from Orwell's novel - written in 1948 and published the following year - was the idea of the Ministry of Truth, which was basically a propaganda machine which presented history as the rulers wished it to be seen, not as had actually taken place.

"Fake news" was a big thing in the media at the time of writing this episode, coming especially from the first Trump presidential campaign where anything negative was dismissed as made-up. It continues to this day.

Whithouse was notified that his episode would be the one where the Vault would finally be opened, and so Missy would feature once again.

It was originally intended that her prison would be a spartan affair. It would be she who would give the Doctor the solution to defeating the Monks, having had previous dealings with them.

The episode opened with a collage of fake history, as presented by the Monks. They would appear in artworks, photographs and newsreel footage, being present at a number of momentous world events as well as appearing in some of the Doctor's own adventures, dealing with Daleks, Cybermen and Weeping Angels.

Moffat had already used this technique to plant the Silents throughout history. Woody Allen had built a whole movie around the idea - 1983's Zelig.

Instead of Orwell's Thought Police, Whithouse introduced the Memory Police - who arrested people who harboured memories of real history.

Having events move on by 6 months from the previous episode, with the Earth already subjugated, reminds us of The Last of the Time Lords. In this, the Master had built a gigantic statue of himself.

A statue which actually acted as a psychic transmitter / receiver was an idea which featured in Douglas Adams' original idea for what later became The Pirate Planet. Then, it was one built by the Time Lords to absorb negative emotions and so pacify a planet's population. A Time Lord sent to dismantle it was caught up in the works and himself absorbed all the negativity, to become the story's villain.

Ordinarily, the Doctor prevents invasions - but having him have to deal with a planet that has already been taken over goes right back to The Dalek Invasion of Earth.

The Doctor's room on the prison ship was described as looking like the one astronaut Bowman finds himself in as an old man at the end of 2001: A Space Odyssey - a stark, brightly lit white space.

The Monk generating thought waves at the heart of the London Pyramid - described in the script as their Cathedral - was to be seen sitting in the pose of Rodin's The Thinker statue (1880).

Next time: Zulu, but with Ice Warriors...

Inspirations: The Pyramid at the End of the World

 

We explained the general inspiration for this trilogy of episodes last time. Writer Peter Harness's idea had involved "Kung-fu Monks" whilst Steven Moffat had actually considered destroying the Earth - but as separate stories. The showrunner then decided to merge these, plus Toby Whithouse's 1984 Orwellian society drama, into a single storyline.

Harness wanted his episode to be a comment on current world affairs, similar to what he had done with his Zygon two-parter the series before, which had dealt with issues of radicalisation amongst young Muslims. The background was Donald Trump's first run for the Presidency of the United States. He felt that what Trump was offering to the American people was simply a short-term fix, one that might prove disastrous in the longer term.

The aliens would therefore appear benign initially, in order to take in their intended victims. This idea had been used before by Bob Baker & Dave Martin in The Claws of Axos - an idealised family group of golden skinned humanoid, bearing gifts, who were actually tentacled monsters, out to destroy all life on Earth. It was also the M.O. of the Nimon in The Horns of Nimon. 

He hit upon the aliens as monks - generally peace-loving, spiritual individuals.

The "Kung-fu" aspect came from the fact that they were initially supposed to have martial arts skills.

They would turn out to be blackmailers from another dimension, who observed probabilities to seek out points in time when a race might be at its most vulnerable, then step in to appear to offer salvation.

Researching potential flash points in recent history, Harness noted an occasion when a Norwegian rocket was launched from the US for scientific purposes, but was mistaken for a missile by the Russians in 1995, and another incident in 1983 when the Russian satellite defence system had erroneously flagged up an attack.

It was going to be revealed that the Monks had tried to intervene before during these events, as well as the Cuban Missile Crisis of 1963, but this information had been supressed by the three major powers.

For his episode, he decided to go with a story he had read about an artificially created soil bacteria named Klebsiella planticola, which broke down plant waste and turned it into ethanol. However, this had only ever been tested in laboratory conditions using sterile soil, and in nature it would prove to be much more powerful - potentially destroying healthy plants.

We are naturally reminded of the insecticide DN6 in Planet of Giants, which appears effective to its creator in the laboratory but will actually destroy all insect life, including that which is essential for agriculture. Harness was actually going to call his soil bacteria DN8, and it was to have been manufactured by Global Chemicals - the company responsible for The Green Death.

This was changed as there is a real company of that name, though one which has never knowingly created a race of giant maggots (as far as we know...).

Hungover lab assistant Douglas was to have had a conversation with Erica about boiled eggs for lunch - a nod to the discussion between scientists Phillips and Goodge in Terror of the Autons.

Harness looked to his Zygon story for other elements. The Doctor would once again be made President of Earth, and the Monks would arrive in the disputed region of Turmezistan. This was where the Zygon rebels had established their base. Here, it is a potential point of conflict between the US, Russia and China.

Whilst the UN features, through the presence of its Secretary General, UNIT does not - despite this being right up their street. (UNIT had become disassociated from the United Nations back in The Sontaran Stratagem, but as an independent multi-national organisation you would have thought they ought to have been involved. They had actually been included in Harness's original storyline, including the return of Kate Stewart. She couldn't appear anyway as Jemma Redgrave had just taken on a regular role in Holby City).

The appearance of the Monks as mummies came from images Harness had seen of mummified corpses in catacombs, which he thought would make for a striking visual image.

Bill's role had to be pivotal. It would be she who would permit the Monks to intervene on Earth - more for saving the Doctor than for the whole world. His blindness - introduced in Oxygen by Jamie Matheison and carried over by Moffat, would lead to him having to be saved.

Bill was originally going to appear to have been vapourised by the Monks on her acceptance of their help, which would form part of the cliffhanger for resolution in the next episode.

Mention is made of the Doomsday Clock. This was created in 1947 by the Manhattan Project scientists to measure the imminent danger of human-made catastrophe. Midnight would signal the end of the world. As of January 2026 it has been set at 85 seconds to midnight - the highest it has ever been. This is due to the on-going risk of nuclear warfare, as well as the mounting concerns about the climate and the rise of Artificial Intelligence.

Next time: The Monks party like it's 1984. The Doctor looks like he's gone over to the dark side, until Bill shoots him...

Inspirations: Extremis

Extremis did not start life as the first episode of a trilogy. Toby Whitehouse was working on a script involving an Orwellian society similar to 1984, whilst Peter Harness had an idea involving Kung-Fu monks.

Steven Moffat himself was pondering something big for the middle of the series - the destruction of the Earth, until he realised how that would impact future storytelling.

Moffat had then agreed to carry on Jamie Mathieson's idea of having the Doctor remain blind after the conclusion of his episode Oxygen.

The showrunner decided to bring these various threads together.

Basically, alien monks would almost bring about the end of the world, but usher in instead a dystopian Orwellian society. The Doctor's disability would - at least initially - prove a handicap to countering this threat.

Bill's role in events would be pivotal in the trilogy's development. It was also planned to make this the time to reveal who was in the Vault.

Moffat needed a starting point which he would write himself, and that's where this episode comes in...

Much of the episode is set in the Vatican's secret library - the Archivum Secretum. Part of the Vatican Library, it contains papal documents including letters to and from international leaders, as well as historic artefacts such as the trial record of Galileo, the Bull excommunicating Martin Luther, and Henry VIII's petition to have his marriage to Catherine of Aragon annulled.

It also contains documents regarded as heretical, and many believe that it holds secret evidence which would actually undermine the Vatican's authority - or even destroy the very foundations of Christianity, deliberately suppressed.

This takes us into Dan Brown territory. He has written a number of potboiler thrillers, some made into movies starring Tom Hanks, which were themselves inspired by supposedly factual books written by - amongst others - the co-creator of the Great Intelligence and the robot Yeti.

A court case cleared Brown of wilfully plagiarising The Holy Blood and the Holy Grail, a 1982 work by Michael Baigent, Richard Leigh and Henry Lincoln, despite The Da Vinci Code (2003) clearly being inspired by its hypothesis - namely that Jesus had a child with Mary Magdalene and eventually founded the Merovingian dynasty. The Vatican allegedly knows all this but suppresses it, but it is knowledge preserved by a secret society known as the Priory of Sion.

Instead of a murder in a museum triggering a story, here we have a bizarre suicide in a library - which turns out to be one of a series of similar deaths. All are people who have read a book - the Veritas. 

The story's title Extremis can mean "at the point of death" (Missy's execution and the "deaths" of the virtual Doctor and companions), or to refer to an extremely difficult situation - something pushed to its furthermost limit.

Another literary inspiration, involving murder in an ecclesiastical library and the suppression of secret knowledge, is Umberto Eco's 1980 novel The Name of the Rose. This has also been adapted for cinema (1986) as well as a 2019 TV mini-series.

Whilst Presidents and Prime Ministers were fair game in drama, Moffat was concerned about the inclusion of the Pope in the episode, not wishing to cause offence, and he actually had the BBC clear this in advance. Whilst scenes involving the fictitious Pope are humorous, he is not himself made a figure of fun. Unlike other figures of authority over the years, the Doctor shows him respect.

The Doctor claims to have known Pope Benedict IX, who was Bishop of Rome in 1045. Benedict - real name Theophylact of Tusculum, reigned three times between 1032 and 1048. One of the "Bad Popes" he was deposed, resigned and sought to enrich himself from the position - even selling the Papacy at one point.

His life was reputedly one of scandal, including murder, rape and sodomy. He may possibly have been the youngest ever Pope, as one record claims he was only 11 or 12 when he ascended the Papal throne, though others claim he was aged 20.

A woman was alleged to have become Pope in the 9th Century, known as Pope Joan. This story only surfaced in the 13th Century and is believed to be pure fiction.

She was only found to be a woman when she gave birth during a procession, and future Popes avoided the spot where this was supposed to have happened. Belief in her existence was such that, until 1600, she had a statue amongst all the other Popes in Siena Cathedral. It was remodelled to make it masculine.

A ritual was created to ensure that no other woman could ever become Pope. During their coronation, an official would physically check their genitalia on a special chair.

One other area Moffat wanted to include in the episode was the notion of reality being an artificial construct. This had featured in several scientific and philosophical theories, but became famous through The Matrix film franchise.

Basically, we are all living in a Virtual Reality simulation, and occasionally there are glitches which reveal this fact.

The VR reveal takes place at CERN - the European Laboratory for Particle Physics. The organisation behind it was founded in 1954 and it was originally based at the University of Copenhagen under Niels Bohr. It later moved to Switzerland. It is best known for the Large Hadron Collider - a circular tunnel 27km in circumference, inaugurated in 2008. Some people at the time believed that it would create a Black Hole and destroy the planet. (Its opening was marked by a BBC radio Torchwood drama).

Moffat's son Joshua had just served a summer internship at CERN prior to studying Physics at university.

The oval-shaped doorways to other simulated locations were based on the video game Portal.

Nardole likens this to the Holodeck in Star Trek: The Next Generation, which was based on an episode of the animated series.

The story ends with a confrontation between the Doctor and one of the Monks in the Oval Office in the White House - a location which had featured prominently in The Impossible Astronaut / Day of the Moon.

The idea that a would-be invader might use a simulation as a precursor to invasion goes back at least as far as the Cold War. It was claimed that fake English villages were built behind the Iron Curtain to train spies.

This crops up in a number of TV dramas, such as Danger Man and The Avengers.

In Doctor Who we had seen it most notably in The Android Invasion, where the Kraals create a mock-up village of Devesham to test out their androids.

Before the Flood, just the season before this one, had been set partly in a fake Russian village in a Scottish valley in the 1980's.

After considering various characters such as Davros for the Vault inhabitant, Moffat had quickly decided on it being Missy. He knew that the mystery could not be sustained for the entire series, so opted to have her revealed at the mid-point. Moffat wanted to examine a new dynamic between her and the Doctor, which would feed into the later stages of the season. Missy is beginning to question her previous lifestyle and is apparently seeking redemption and a change from her evil ways.

The flashback sequences to the Executioners' planet also allowed the audience to see how Nardole came back into the Doctor's life - sent by his wife River Song. He has her journal - first seen in Silence in the Library / Forest of the Dead.

It is said that Time Lords have three brain stems, which confirms Missy's advice that Kate Stewart use two additional snipers in The Magician's Apprentice.

She claims to have known about the Doctor's retirement to Darillium from the Daleks - referencing both The Husbands of River Song and The Witch's Familiar.

Next time: the Monks set up a pyramid scheme, and we learn of the dangers of going to work with a hangover...

Inspirations: Oxygen

In 2005, former CEO of Nestlé Peter Brabeck-Letmathe tried to argue that water was not a human right. It was simply a commodity like anything you might buy in a shop, and had a market value.

By 2013 he had backtracked in his view, following the understandable outcry. 

It's this sort of commercialisation of what most would agree to be a basic human necessity which forms the backdrop to this episode.

We are in deep space, and the essential element here is oxygen. A mining rig on an otherwise lifeless asteroid is owned by a faceless corporation on Earth, and its crew have to pay for their air supply.

There's no safety net. If your stock runs out, you suffocate and die.

The story began life as a request from Steven Moffat to writer Jamie Mathieson for an adventure set in outer space. The showrunner wanted it to highlight just how hostile and deadly space could be. He had been inspired by the recent movie Gravity and the 1995 film Apollo 13.

Mathieson's original idea was of a spaceship graveyard. A group of survivors were being forced to jump from wreck to wreck in search of oxygen and other supplies, hunted all the time by savage crystalline monsters.

They were controlled by a queen who dwelt on a nearby asteroid. She mimicked distress signals to ensnare passing ships. An additional complication was that the survivor group consisted of people from opposing factions in a war. There was also an element of The Thing, in that the monsters could mentally manipulate people, so paranoia was rife amongst the survivors.

The story would have ended with an ethical debate about whether or not they should kill the queen.

It was then decided to ditch the monsters, other than the queen, and simply have space itself the threat, but with the additional danger of zombies - animated human cadavers. These would have some sort of intelligence, however. It was the queen which controlled them. 

The spaceship graveyard was still the setting, and the people encountered by the Doctor and Bill were now simply shipwrecked scavengers.

This time, the episode ended with the Doctor forming a psychic link with the queen to stop it from killing.

Two of the characters were named after family friends of the writer - Darren and his son Ivan, who was a fan of the show. The former became Dahh-Ren, who was originally going to have a multi-eyed spider-like face. Budget restraints reduced this to him simply having blue skin.

As much as Moffat liked the story, he asked Mathieson to pare it down to essentials. He proposed that the zombies be manipulated by their spacesuits. He was worried that they might resemble too closely the skeletons in spacesuits from his own Silence in the Library / Forest of the Dead.

The more zombified look of the cadavers - exposed to the vacuum of space - was retained.

It was Moffat who then suggested that the crew of a mining vessel be forced to purchase their oxygen from the corporation which employed them. This could be withheld if the operation was unprofitable.

An added threat was that the smartsuits could electrocute their owner or anyone they touch.

The suits quite literally become the menace.

"Suits" is slang for business executives and bosses - i.e. the men in suits who run things.

Together Moffat and Mathieson decided on bringing back GUS from the writer's previous story Mummy on the Orient Express, whose origins had been left vague. This would stand for Ganymede Systems.

Mathieson then drew on his own experience of working long hours for bad wages for large corporations.

In the end, the references to GUS would be dropped.

The mining vessel was named Chasm Forge, after the Valley Forge from the 1972 ecological sci-fi movie Silent Running.

Mathieson proposed that the Doctor should be blinded for the second half of the story, after sacrificing his sight to save Bill. He later suggested that the Doctor remain blind at the end of the story - expecting this to be rejected. Moffat decided to incorporate this into the next two scripts.

Nardole's role in Series 10 had only developed late in the day, and he was originally going to be brought into the story after the Doctor and Bill set off without realising he was on the TARDIS.

He didn't feature in the earlier drafts.

At one point the Doctor lies to Nardole about one of the fluid links. He had first used these as an excuse to explore in The Daleks, and they were a feature of other stories such as The Wheel in Space and The Mind Robber.

The Doctor had previously been seen to do a space walk, in a helmet with oxygen but no face visor, in Four to Doomsday, where he claimed to be able to survive this environment for up to 6 minutes.

Next time: monk-y business in the Vatican...

Inspirations: Knock Knock

A fairly straightforward one this, as it's another attempt to do a "haunted house" story in the series. There had obviously been an element of this previously in Blink, and more so in Hide. 

Specifically, what inspired writer Mike Bartlett were those odd creaks which people hear in the middle of the night, or when you are supposedly all on your own in an empty building... 

Promoting the series Doctor Foster, Bartlett had mentioned that he was a Doctor Who fan, and this was noted by the series' script editor - Lindsey Alford - who then mentioned it to her husband, who just happened to be its executive producer Brian Minchin.

Steven Moffat assumed that the writer would be far too busy to submit anything as his own series had a second season commissioned, but Bartlett insisted he would make the time.

Sent away to think of an idea, he hit upon creaking floorboards, and pondered if these were caused by something within the very fabric of a house. There would be something hidden in the attic, and the walls would move.

Always a fan of exploiting a common fear for the show, Moffat was pleased with the concept.

Thoughts about the housing crisis led him to plot a story about a group of people forced to move in and share - only to be picked off one by one by whatever lurked within the house. When given details about new companion Bill, who was to be a university student, it made sense to have the sharers a group of her student friends moving in together.

Bartlett had once lived in a big Victorian house in Yorkshire as a student, which had a basement that looked like a dungeon.

The menace in the walls would be giant insects, and Bartlett named these Dryads - after the wood nymphs of Greek mythology.

"Drys" is the Greek word for oak, and it was initially believed they were specifically spirits of those trees. Tied to a particular tree, they died when it died, so they weren't immortal. Their appearance changed with the seasons.

Two notable Dryads were Daphne - who was transformed into a laurel tree to avoid the unwanted attentions of Apollo - and Eurydice, wife of Orpheus, whom he tried to bring back from the Underworld.

Bartlett envisioned actors Mark Rylance or Stephen Rae for the Landlord - a mysterious man in a brown suit. In the end, he would be gifted David Suchet, famous for his long-running TV role as Poirot, which ran from 1989 to 2013. (Peter Capaldi had featured in the third season story Wasp's Nest).

Suchet accepted the part without even asking what it was, so pleased was he to appear in the series.

The look came from a man who used to visit his parents, but the brown suit fits with the general colour palette of the episode. It was intended that the house would have wooden doors and wood-panelled walls.

The thing in the attic would prove to be a wooden woman - inspired by The Sandalwood Girl. This 1985 children's novel was written by Sheila K McCullagh, and Bartlett had been reading it recently to his son.

In the first draft, the house would give up all its victims at the end - going back every 30 years, to 1937. The Doctor would offer to get them all back to their own times in the TARDIS. The first disappearances, according to the second draft, were in 1927.

Until late in the day, the house was to have been restored at the end of the episode, but this was changed in order to explain why Bill would be back staying with her foster mother again later.

One of Bill's new flatmates is named Harry, and it was originally intended that he would be the grandson of former companion Harry Sullivan. It was decided that this was too obscure a reference and was dropped - despite Harry being referred to fairly prominently in Inversion of the Zygons only the year before...

Harry was then going to become an ancestor of one of the colonists from the earlier episode Smile.

At one point the Doctor talks about "going up the wooden hill" - meaning up the stairs to bed. (The full saying is "up the wooden hill to Bedfordshire"). He had previously used this phrase to Ace in Ghost Light, which Bartlett considered another inspiration.

The building is described by student Shireen as a "Scooby Doo house", as in the spooky mid-1970's cartoon series featuring a Great Dane and a bunch of teenage mystery solvers. 

Larry Nightingale had described Wester Drumlins in the same way in Blink - and the same location was used both in that story and in this, though a different section of the building.

David Suchet would be surprised to discover that his family had rented the property for a holiday a couple of years before.

Telling the students about the time he helped out musician Quincy Jones, the Doctor mentions that he had a Klarj Neon Death Voc-Bot for a bassist - presumably a reference to the ones seen in The Robots of Death.

Next time: The Suits get you every time. Bill encounters zombies - in space. The Doctor turns a blind eye...

Inspirations: Thin Ice

The phrase "on thin ice", meaning to be in any potential danger, first appears in an essay by Ralph Waldo Emerson in 1841.

As a story set around a particular historical event, that's our obvious starting point.

As already mentioned, new companions tended to get the same trio of introductory story types, with the third one being a trip into the past.

Steven Moffat had been impressed with Sarah Dollard's previous story - Face The Raven - and asked her if she had any other ideas. 

A friend of hers had done a lot of research on the last great Frost Fair on the Thames for another project, which had also intrigued Dollard. 

Originally the Doctor was to have taken Bill to visit it deliberately, but this was later amended to be a random visit by the TARDIS.

The river Thames used to freeze over frequently, with the first ever recorded mention back in Roman times.

Henry VIII is said to have used a sleigh instead of his usual barge to travel between Westminster and Greenwich in 1536.

The river used to be slow moving, the climate colder thanks to the Little Ice Age, and London Bridge's 19 piers interfered with the flow of the Thames - ideal conditions for it freezing over during particularly severe winters.

Staging a fair on the ice, in the centre of London, took place for the first time in 695. Others followed in 1608 (the first time the setting up of stalls and entertainments on the ice was actually called a Frost Fair), 1683-84, 1716, 1739-40, 1789, and finally in 1814.

The freeze of 1683-4 was notable for lasting nearly two months. An entire street was built across the Thames from Temple to Southwark, with hackney coaches running its length. When the thaw finally came, a ship moored against a riverside pub broke free and pulled the building down, killing 5 people.

The last time a significant section of the Thames froze over was the winter of 1962-63, in the upper part of the river.

These Fairs ended due to climate change and the demolition of London Bridge in 1831, followed by the building of the Victoria and Albert Embankments which channelled the river quickly through the city.

It is the Frost Fair of 1814 which interests us, however.

The previous episode - Smile - had ended with the Doctor and Bill emerging from the TARDIS to find themselves not where they expected to be - back at St Luke's University. Instead, they had seen ice, and an elephant wandering towards them from out of the fog.

This was one of the most famous events of the 1814 Fair - the ice so thick that an elephant could be led across it by Blackfriars Bridge. The freeze began just after Christmas, 1813, and lasted until 7th February 1814.

As well as food and drink stalls, there was dancing and nine-pin bowling, and a dozen or so printers set up their presses on the ice to print souvenir pamphlets about the Fair.

When the thaw came, a number of people drowned.

The Doctor fails to mention to Bill that he visited this very event with River Song, when he got Stevie Wonder to sing to her for her birthday - as mentioned by her in A Good Man Goes To War.

The Big Finish audio "Frostfire" claims that the 1814 freeze was caused by an alien, whilst different Doctors and companions had visited earlier Fairs in novel and comic adventures.

Whilst the setting for Thin Ice might be the Frost Fair, the actual story revolves around a gigantic serpentine creature trapped beneath the ice in the Thames, which is being exploited by a ruthless peer of the realm during the Industrial Revolution.

The idea for a serpentine entity came from Steven Moffat observing that the Thames, as it appears in the opening credits to EastEnders, looks like a giant snake.

The showrunner was also interested in doing a story involving a sea monster, thinking of movies such as The Beast From 20,000 Fathoms (1953) and The Giant Behemoth (1959).

Lord Sutcliffe is the villain of the piece, and he has somehow discovered that the creature's excrement can be processed to become a fuel source, capable of providing great heat.

In a nutshell, the Industrial Revolution came about in Great Britain due to the coming together of several key components - readily available resources of water, wood, coal and iron ore, plus the men (and it was mostly men) who had either the vision or the money to exploit them. These were the inventors, and the businessmen / land owners who were wealthy enough to commission the ideas of the former and put them into money-making practice.

Wood, coal and charcoal could only burn to a certain temperature, and to create certain metals this wasn't high enough. New methods of producing power were invented, in the hope that greater, more sustainable, temperatures could be achieved, and so stronger metals could be produced.

There's a lot more to the Industrial Revolution than that, of course, but this is the key element as it relates to this story.

On top of his exploitation of the creature, Sutcliffe plans to bring about the destruction of the ice whilst the Fair is in full swing, as a means of feeding it and so increasing its "output".

And he's a racist to boot.

Whenever a new companion makes their first visit into the past, they often speak about two issues - the "if I step on a butterfly will it change the future?" scenario (as in Ray Bradbury's A Sound of Thunder short story of 1952); and - if they are Black - will they be carted off as slaves. 

We saw this first with Martha Jones on her visit to Elizabethan London in The Shakespeare Code, and it gets a mention again here. In both cases, the Doctor points out that the city has always been more cosmopolitan than people think, and we see a wide range of ethnicities amongst the background cast.

The Doctor here talks about the "whitewashing" of history, though the danger is that the programme is actually presenting an idealised version of the past which ignores the racism of the time.

The idea that Sutcliffe is somehow atypical of early Victorian Britons, of any class, in his attitudes is a bit of a nonsense.

The children whom the Doctor and Bill encounter are orphaned street-urchins who make their living scavenging and stealing - which naturally makes us think of the juvenile pickpocketing gang recruited by Fagin in Oliver Twist or, The Parish Boy's Progress, by Charles Dickens (1838). One of the gang - a boy nicknamed "Spider" - steals the sonic screwdriver and is subsequently killed after being pulled under the ice, eaten by the creature. This is an extremely rare instance of a child being seen to die in the series. His bright red hat stands out, which is presumably a directorial nod to the girl in the red coat in Steven Spielberg's Schindler's List.

The Doctor tells the children the story of Der Struwwelpeter, or Shock-Headed Peter - an 1845 German children's book. Written by psychiatrist Heinrich Hoffman, this comprised ten stories which each had a cautionary element, where naughty behaviour has a nasty consequence for the children involved.

Steal sonic screwdrivers - get eaten by sea monsters...

Pie Men were a common sight in Georgian and Victorian London, walking the streets with a tray of freshly baked pies - usually meat but often eel - on their head or strapped to their waist. The best known example in literature is the one met by Simple Simon in the nursery rhyme. Unfortunately, the quality of the contents of the pies varied considerably - hence their cheapness.

Not perambulatory, another famous fictional pie seller is Mrs Lovett, who made her wares from the victims of Sweeney Todd, The Demon Barber of Fleet Street...

Next time: Who's there? The series' oldest gag gets an airing as the Doctor helps Bill move into her new accommodation. No jokes about wooden acting, please...

Inspirations: Smile

As with previous new companions up to this point, the usual pattern of (mostly) contemporary Earth setting, followed by far future adventure, followed by a trip to a historical period, was decided on for Bill. Smile would be her future story.

The reason we concentrate on just her and the Doctor for much of the running time was simply to establish their relationship.

Writer Frank Cottrell-Boyce had previously contributed the story In the Forest of the Night in Series 8 - a fantastical premise which would surely have seen Chris Bidmead's head explode on DWM's "Bidmead-O-Meter", which rated stories with utterly daft science.

For his next submission, he decided to provide something based much more on real science.

Preparing for an anthology of science fiction short stories, Cottrell-Boyce had approached a scientist working at the Jodrell Bank radio telescope, to discuss how humans might in future colonise other planets. He was advised that this would likely be done by sending robots on ahead to prepare the way.

Noting the preponderance of dystopian futures laid out in the genre, the writer wanted to present a utopian society, in which the lives of the human colonists were regulated by robots and artificial intelligence, working to their benefit. This then led to thoughts about what rights these robots / AI would have were they to become self-aware.

Steven Moffat was pleased with this as a backdrop to a story, which does not surprise as "AI gone wrong" had already been used by him on more than one occasion. It had taken over from the "mad computer" style of story, variations of which ran throughout the classic series.

Cottrell-Boyce had noted the increasing use of emojis which were being employed more widely. He saw these as a new language, which had begun to grow beyond social media.

Peter Capaldi and Moffat both explained on Doctor Who Extra that they neither used nor fully understood emojis, but Jenna Coleman had used them all the time, rendering some of her texts to them near unintelligible.

The Emojibots were originally envisioned as simple boxes with arms, with a screen on the upper surface on which they would communicate by displaying emoji icons. They were not intended to have any human-like form.

As well as the Emojibots, Smile features nanobots named Vardies. This derived from the scientist Dr Andrew Vardy, who researched swarm robotics at the University of Newfoundland in Canada. He had attended a conference in 2013, one of whose aims was to link scientists with authors. Vardy and Cottrell-Boyce collaborated on a story the following year.

Insect-like in the final programme, they were originally intended to be hedgehog-like in appearance.

The writer named the colony world Erewhon - an anagram and near palindrome of "nowhere". There are two possible inspirations for this. 

The first is the 1872 novel Erewhon: or, Over the Range, by Samuel Butler. This told of a utopian country and acted as a satire on Victorian society. One aspect of this was that the sick were branded as law-breakers, as they could not uphold the general happiness expected of the inhabitants.

Then there is News From Nowhere (Or an Epoch of Rest), written by William Morris in 1890 which told of another utopian society.

As the working title for Smile was "News From Nowhere", we can assume the latter - though Morris may have himself been inspired by Butler's work.

In the finished story, it is only the colony ship which is named Erewhon, and the planet has the designation Gliese 581D. Gliese 581 is a red dwarf star around which a "Super Earth" exoplanet was discovered in 2007 - Gliese 581c. It is 20.4 light years from Earth in the constellation of Libra, makes a complete orbit in 13 days, and has one hemisphere permanently facing its star. In terms of surface conditions, it is thought to resemble those on Venus.

An Earth colony in which the populace are forced to be happy is not a new idea for the show. The concept featured in The Macra Terror, and in The Happiness Patrol.

At one point the Doctor quotes David Bowie: "I'm happy, hope you're happy too", from his 1980 hit Ashes to Ashes.

The Doctor states that the Scots seek independence on every planet colonised. A referendum was underway at the time of writing. Scotland going it alone after abandoning Earth had also been mentioned in The Beast Below.

Steadfast is said to be a MedTech One grade. 'MedTech' was the designation given to Vira in The Ark in Space - suggesting that these colonists may have left Earth not long before the solar flares which led to the setting up of space station Nerva as a sanctuary.

Ralf Little had featured in the movie 24 Hour Party People - which was also written by Cottrell-Boyce.

The colony ship is said to have a Fleishman Cold Fusion Engine. This was named after Martin Fleishman, a chemist who had claimed to have discovered cold fusion.

Noting how the seats in the TARDIS are so far from the console, Bill asks the Doctor if he has stretchy arms like Captain Fantastic of Marvel's Fantastic Four. She also asks if they have to wear seatbelts whilst in flight. The TARDIS had been seen to have safety belts, which attached to the console itself, in Timelash.

Next time: The Doctor and Bill return to Earth and meet with a frosty reception...

Inspirations: The Pilot

Not to be confused with the unscreened version of An Unearthly Child, which is often referred to as "The Pilot" - but for Steven Moffat it was designed to fulfil the same purpose of allowing people to start watching the series. The term employed was a "soft reset".

This wasn't something new for the series. As well as the obvious relaunches - the 1996 TV Movie and Rose - there were also soft resets with The Tomb of the Cybermen and Spearhead From Space in the classic era, designed to act as jumping-on adventures for new viewers. The Eleventh Hour also sees the series dispense with all associations from the previous RTD era.

The only character already established here, other than the Doctor, is Nardole, who has appeared in the last two Christmas Specials - but knowing who, or what, he is isn't important right now.

Clara has gone, and River Song's story has finally been wound up. You'll recall that Moffat hadn't known he was going to be producing a sixth season - expecting Chris Chibnall to take over with his own new companion, and he had cleared the decks to facilitate this.

Time has moved on for the Doctor and he is now lecturing at a university - something he has been doing for quite some time we learn. There's a big metal vault in the cellars which has something to do with why he is here. There's a Police Box in his rooms, and on his desk are a mug full of sonic screwdrivers, and photographs of his granddaughter Susan and River Song - his first and last to date companions. The desk items are there to please the existing fans and to establish that this is a continuation of a series which began in November 1963, without alienating new viewers.

We find out what this is all about through the eyes of the new companion, Bill Potts, who is the first openly gay companion in the series (Captain Jack slept with anything). She serves in the university canteen but wants to better herself, and the Doctor sees the potential in her - electing to allow her to join his lectures whilst tutoring her privately. She is the agent through which the new viewers get into the series.

This was inspired by a performance of Educating Rita which Moffat had seen in Glasgow. This 1980 Willy Russell play told of the relationship between a working class Liverpudlian hairdresser and her older, boozy college professor, and how each ultimately has a positive impact on the other. It was adapted for the cinema in 1983, starring Michael Caine and Julie Walters.

The plan was to have a funnier companion, straight talking, who would ask the sort of questions which the audience might ask and view things through their eyes. They would also be shown to have watched sci-fi films and TV series, as Moffat had noted that people in Doctor Who rarely acted like they had seen time machines and aliens on screen. For instance, the Doctor tells Bill that the TARDIS has a "cloaking device", just as he had done in the TV Movie - but here he's using language someone who has seen Star Trek would understand.

As well as her sexuality, it was decided that Bill should also be non-white, following criticisms about lack of diversity and representation in Doctor Who and other popular dramas, made by Sir Lenny Henry in a BAFTA speech.

Casting for Bill - a name Moffat heard David Tennant call Billie Piper during production on the 50th Anniversary story - carried a codename. This was "Meantown" - an anagram of 'Woman Ten', as in the female companion for the tenth series. Meantown was also a placeholder title for the story in its earliest form.

Three audition pieces were written, which all found their way into the series in one shape or form. The first was the companion talking about someone she fancied who she serves in the canteen (a boy at this stage). The second was their introduction to the TARDIS interior after escaping from some robots. The companion argued that there was no protection inside a small box made of wood. The third scene was set in a corridor in a Dalek city, where the companion made comments about the monsters' stair-climbing capabilities and kitchen / bathroom appliance design elements.

Once cast, Pearl Mackie wanted to view some old stories but Moffat discouraged this - feeling her lack of knowledge about the series and its tropes would benefit her performance.

The working title for the story became A Star In Her Eye - a reference both to the fact that Bill's would-be girlfriend Heather has an actual star shape in one of her eyes, and to Bill's growing admiration for the Doctor.

The Doctor hangs an "Out of Order" sign on the TARDIS door - just as he did in The War Machines.

The biggest fan-pleasing moment is when the TARDIS arrives in the middle of a Dalek battle. We see that they are fighting the Movellans. The Dalek-Movellan war was first introduced in Destiny of the Daleks, and its outcome formed the background to Resurrection of the Daleks.

Bill was first introduced to the public in a mini-episode titled Friend From The Future, filmed on this futuristic corridor set and featuring a Dalek.

Early in the development of the season, Moffat considered the occupant of the mysterious vault to be either Missy or Davros. Fan speculation was that it might be Susan, after seeing her photograph on the desk - the reasoning behind which was that she had been placed in the vault to protect her from the Time War.

Next time: AI Goes Wrong No.632. Yes, it's the return of one of Mr Moffat's favourite story ideas. The Doctor and Bill visit a beautiful colony planet, but find little to smile about...

Inspirations: The Return of Doctor Mysterio

This one wears its inspirations very much on its sleeve: Doctor Who does comic book superheroes in general, and DC Comic's Superman in particular.

Steven Moffat came up with the idea as the Doctor hadn't ever met a "real" superhero before - only the fictitious Karkus in The Mind Robber. He felt the idea would be good for a festive special due to the popularity of movies of this genre, especially the blockbusters of the Marvel and DC universes.

He loved the notion that nobody recognised Clark Kent as Superman just because of a pair of glasses - mentioned by the Doctor in Grant's bedroom - and also the fact that Superman movies involved a love triangle with only two people in it.

The principal inspirations given by Moffat were Superman (1978) and the TV series Lois and Clark: The New Adventures of Superman, which ran for four seasons between 1993 - 1997.

It had been hoped to film in New York City itself, as had happened back in 2012. New York City was the inspiration for both Metropolis and Gotham City.

The story starts with the Doctor in the Big Apple attempting to counter the problem which arose in The Angels Take Manhattan, where all of the temporal paradoxes generated by the Weeping Angels have resulted in it becoming a no-fly zone for the TARDIS (though how he got here now, if that's the case, is anyone's business).

His gizmo to resolve this requires an ultra-rare alien crystal, but young Grant - who is a comic book fan judging from his posters and Marvel-themed wallpaper - inadvertently swallows this, thinking it medicine.

This crystal won't pass through the body, but will instead cause the boy to develop superpowers.

He goes on to adopt a superhero alias - The Ghost - who is masked, wears a cape, and has an initial emblazoned on his chest as part of his costume.

Abilities include super-strength, X-ray vision and the power of flight.

The costume was designed to incorporate elements of both Superman and Batman.

Grant later grows up to be a mild-mannered, bespectacled young man, who works as an au pair for Lucy Fletcher, a reporter just like Superman's Lois Lane. Her surname was originally going to be the alliterative Lombard, but this became her married name which she no longer uses. Lucy is the name of Lois Lane's sister.

Clark Kent and Lois worked for the "Daily Planet" newspaper, whose building sported a huge globe on its roof. The HQ of the Harmony Shoal Corporation here has a similar globe on its roof.

During a press conference there, attended by Lucy, there's mention of individuals named Shuster and Siegal. Joe Shuster and Jerry Siegal were the creators of Superman.

The villains this time are related to characters seen in the previous Christmas Special. Then known as the Shoal of Winter Harmony, here they represent the company Harmony Shoal. Both are humanoid in form but with a scar running diagonally across the face, and can open up their heads. Here, we learn that they are human, with a parasitic brain-like creature inserted into their skull.

Also from The Husbands of River Song comes Nardole. The Doctor has fashioned an artificial body for him, after being beheaded by King Hydroflax's robot host on their first meeting. Nardole was introduced to give the Doctor someone to talk to and explain things as he didn't interact with Grant much in the second half of the episode.

At one point we see The Ghost stop a spaceship from crashing into New York, holding its nose in his hand. This same imagery appears in 2006's Superman Returns where he stops an aircraft crashing into a baseball field during a game.

When The Ghost first rescues Lucy, he tells her he hopes the experience hasn't put her off journalism - just as Superman had said to Lois in the first Christopher Reeve movie, after rescuing her from a crashing helicopter.

A roof top date is also arranged here and in Superman.

The Doctor at one point uses the phrase "With great power comes great responsibility", which is synonymous with Spider-Man.

Justin Chatwin (Grant) opted to use a deeper voice when in his Ghost guise - something he picked up from Michael Keaton's performance as Batman.

Though not mentioned on screen, Grant's surname was Gordon according to publicity materials. This is another example of the alliterative names often associated with comic book characters, and is also the name of the police commissioner who works with Batman.

When the young Grant floats up to the top of the Empire State Building, the set was actually constructed horizontally - a nod to the famous sequences, usually involving a celebrity cameo, of Batman and Robin walking up the side of a building in the 1960's series starring Adam West and Burt Ward.

The Doctor distracts the employees of Harmony Shoal in Tokyo by generating Pokémon characters in the vicinity. This obsessive virtual collection phenomenon first came to prominence in July 2016.

The title of this story came about during the world tour undertaken by Peter Capaldi, Jenna Coleman and Steven Moffat for Series 8, where they learned that the programme was titled "Doctor Misterio" in Mexico. Capaldi loved this and kept repeating it in a deep voice, impersonating the TV announcer.

The movie theatre across the road from Lucy's apartment is showing a film called "The Mind of Evil", title of a Season 8 Jon Pertwee story.

Next time: new companion Bill meets the ultimate stalker, a girl with stars in her eyes who wants to take her away from all this...

Inspirations: The Husbands of River Song

Having penned a story called The Wedding of River Song, it was only natural that Steven Moffat would come up with a title such as this. It is Husbands, plural, as we get to see three other spouses as well as the Doctor. Two elements are introduced which will reappear later - the character of Nardole and the "Shoal" - humanoid in appearance, but who are able to open up their heads, and have a scar running diagonally across their face.

This was to have been Moffat's final episode as showrunner - though he had planned to leave much earlier. Originally he meant to hand over to someone else after three years, ending his run with the 50th Anniversary celebrations. The new showrunner would then have introduced their own Twelfth Doctor at the end of the 2013 Christmas Special. However, he had been unhappy some aspects of his own work on Series 7 and wished to bow out on a more satisfying note. Then, at the end of Series 8, Jenna Coleman decided that she wanted to stay on longer. Moffat wanted to round off her story himself, so this led to Series 9.

Rather than saddle a new showrunner with a companion created by himself, he decided on a one-off companion figure for what he thought would be his final episode.

Russell T Davies had been encouraging him to pair the Twelfth Doctor with River, so he decided that there was one more story of hers to tell.

The idea that she would encounter a Doctor she didn't recognise appealed to him. The Doctor would be able to see what she was like when he was not around (as far as she was aware).

Believing that The Name of the Doctor had been her final appearance, Alex Kingston was more than happy to be invited back.

It had always been known that the final meeting between River and the Doctor would be at the Singing Towers of Darillium, and so this was an obvious setting for this episode. This location had first been mentioned by River in Forest of the Dead back in 2008. This was their last date before her death in the Library. Knowing this, the Doctor had been avoiding taking her there in the special mini-episodes recorded for the Series 6 box-set (First Night / Last Night).

As the Series 4 two-parter had been his last scripts before becoming showrunner, setting a story at the Singing Towers would bring Moffat's own story with Doctor Who full circle.

The person deemed best fit to take over from Moffat was Chris Chibnall. A known fan of the series who had also written for it, as well as co-producing Torchwood, he had raised his profile significantly in the industry with crime drama Broadchurch. Moffat took him out to lunch to sound him out about taking over - only to learn that he was heavily involved with the third season of Broadchurch as well as the launch of a US version. Moffat decided not to even mention the idea of him taking over Doctor Who, and realised that he would probably have to stay on for another year, when Chibnall could potentially be in a better position to succeed him.

This late change of plans, plus his commitments on Sherlock, is the reason why we were about to get another gap year.

Before the Doctor and River got to the Singing Towers, Moffat wanted a yuletide romp inspired by the screwball comedies of Hollywood's golden age. In these, a man and woman were thrown together by a particular set of circumstances and, despite having opposing personalities, had to work together to overcome these - usually disliking each other at first but becoming romantically involved as they got to know each other better.

An early idea was for River to steal the TARDIS, with the Doctor an apparently unwilling companion for her. He would pretend not to know about the ship and act all surprised at what he saw inside. This, of course, made it through to the broadcast episode, and is one of its highlights.

The villain of the piece would be a big, overblown character who wasn't actually all that much of a threat, despite their bluster.

The idea that he had a robot body, with interchangeable heads, was an early one.

Hydroflax is known as the "Butcher of the Bone Meadows". This was another location mentioned by River as appearing in her diary.

For his spaceship, the director looked to old sci-fi movies, especially the saucer which appears in Forbidden Planet (1956). It was designed to also resemble a Christmas tree bauble.

Ramone and Nardole were deliberately cast as being very dissimilar in looks to emphasise River's wide-ranging tastes in men - which included different incarnations of the Doctor.

She said she knew all the Doctor's faces in The Time of Angels, and here we see a folding wallet with photos of the first eleven incarnations.

When the Doctor comments on River's numerous husbands, she counters by pointing out his marriage history - Queen Elizabeth I, Cleopatra and Marylin Monroe as well as herself.

For his date with River, the Doctor wears the suit he had worn on the space-going Orient Express - which was supposed to be his final trip with Clara.

The street in which we first see the TARDIS is very clearly a reused set - the Trap Street from Face The Raven.

When River states that "one should always have something sensational to read on a spaceship" she is paraphrasing Gwendolen in Oscar Wilde's The Importance of Being Earnest, where it is on a train.

Next time: A boy wonder grows up to be a super man, whilst the villains need their heads examining...

Inspirations: Hell Bent

Hell Bent closes the ninth series of the revived Doctor Who, and has the main job of trying to tie up various story arc points - and of writing out Clara Oswald as the companion.

The arc this season has been the issue of "the Hybrid" with a number of candidates put forward - the Doctor himself, the Doctor / Clara, Davros, Time Lords / Daleks, Ashildr, Zygon Osgood...

Steven Moffat also wanted the Doctor to return to Gallifrey to explore some of its mythos - including that of regeneration. He would arrive there as a man out of control - out for revenge for what the Time Lords had done to him in the previous episode, and for what had happened to Clara, even though she had died through her own misadventure and had specifically asked him not to hold anyone but herself responsible for her fate.

One inspiration Moffat had for the Doctor at this time was the character Shane, as played by Alan Ladd in the 1953 Western.

This in turn inspired the director to give the opening sequences at the barn-like building (first seen in The Day of the Doctor and later shown to be a childhood haunt of the young Doctor in Listen) a Spaghetti Western feel.

As well as these elements, Moffat also wanted to conclude Ashildr's story - showing her still living at the end of the universe and therefore older, and somewhat wiser, than the Doctor himself - someone whom he would now listen to.

When it came to looking at regeneration, Moffat had noted that a number of Time Lords had properly died after being fatally injured instead of regenerating, such as the War Chief, Morbius and incidental characters in The Deadly Assassin and Arc of Infinity.

Moffat wrote a sequence in which the Doctor would deliberately 'kill' a Time Lord - though first checking that they were not in their final incarnation. This scene is contentious to say the least, as the Doctor is (a) seen to wield a gun and (b) has zero justification for shooting the General - who regenerates into female form (and a different ethnicity), and who suggests that they have usually been female throughout their existence.

The General, as played by Ken Bones, had been introduced in The Day of the Doctor.

Ohila of the Sisterhood of Karn appears on Gallifrey, having been seen earlier in the opening episode of the series, but first introduced in the 50th Anniversary prequel mini-episode Night of the Doctor. 

The Brain of Morbius had previously stated that Karn was in the same region of space as Gallifrey and there were ancient ties between the Sisterhood and the Time Lords. (Though for her to be here, when Gallifrey is time-locked in a pocket universe at the end of Time, she must have been there on the last day of the Time War - except she's on Karn in The Magician's Apprentice...).

Rassilon also returns, though in regenerated form. (Timothy Dalton was busy making Penny Dreadful in Ireland at the time and unavailable to reprise the role so it went to Donald Sumpter, who had previously appeared in The Wheel in Space, The Sea Devils and SJA: The Eternity Trap).

After banishing Rassilon,  the Doctor assumes the Presidency of the High Council of Time Lords - a role he previously adopted in The Invasion of Time, and which was offered to him again in The Five Doctors. By Trial of a Time Lord we learned that he had been deposed, though the Inquisitor offered the role to him once again - only for him to suggest she take it up herself.

Moffat wanted the original TARDIS console room design to be seen at some stage in the story. One had been recreated for the 2013 drama An Adventure in Space and Time, and this was currently on display at the Doctor Who Experience a short distance from the BBC studios. With the Doctor arriving on Gallifrey via the confession dial, leaving his own TARDIS behind, it was easy enough for a different one to be included as he would require it to get back to his own, left behind in present day London.

The implication is that this is the default interior design for all TARDISes. 

This one has a white console, whereas the Doctor's was seen to be pale green in the Pertwee era, however. (Painted this colour to appear white in B&W of course).

That TARDISes appear to be metal cylinders in outward appearance matches the scene in The Name of the Doctor where we saw the Doctor and Susan first steal the ship. The ones seen in Part 10 of The War Games were more box-like, as was the Master's in The Claws of Axos.

Moffat's decision on Clara's ultimate fate was that she would become a traveller in space and time just like the Doctor whom she sought to emulate - and so this TARDIS could then be given to her.

Moffat never intended Clara to stay dead - a trope of his going back to the many deaths of Rory Williams. (Unfortunately this simply undermines the conclusion to Face The Raven and much of Heaven Sent, which is why so many fans dislike the episode).

The diner is the same one seen in The Impossible Astronaut - really a venue located on Cardiff Bay - with its distinctive Elvis painting on the restroom door.

Making cameo appearances are a Dalek, Cyberman and Weeping Angel in the Cloisters, plus one of the Cherub angels introduced in The Angels Take Manhattan.

Next time: four weddings, but no funeral...

Inspirations: Heaven Sent

Heaven Sent was written both as a showcase for the talents of Peter Capaldi as an actor, and as a challenge to himself by Steven Moffat. He claimed it was the hardest thing he had ever written up to this point. The aim was to show the Doctor in isolation - what he does when he has no-one with him.

No-one to save or protect - or to show off to. Just his own survival.

The castle represented his grief over losing Clara in the previous episode. This proves to be a construct within his own Confession Dial - a device introduced at the start of the series in The Magician's Apprentice. 

Moffat realised that the series had seldom succeeded in presenting grief in a realistic manner. This was especially true in the case of Katrina, Sara Kingdom and Adric in the classic era. The Doctor and fellow companions tended to carry on as though nothing had happened in the very next story.

Nyssa gets over her father's death all too quickly as well - failing to react the way you would expect anytime she meets the Master who has stolen his corpse for a body.

Moffat admitted that he hadn't really managed to handle grief himself in his own series. Amy and Rory have effectively lost decades of their daughter's life when they discover she's River Song, and the Doctor soon forgets about them once the Impossible Girl shows up.

The notion of an individual being repeatedly teleported was one which Moffat had entertained for years, and even considered using for a Big Finish story. He reasoned that if you were continually teleported in this way, you could exist for as long as that technology functioned. 

Star Trek has had characters living well into the future after being saved in the transporter Pattern Buffer (such as Scotty in the ST:TNG episode "Relics"), and ST: Strange New Worlds had Dr M'Benga's daughter saved in a transporter buffer until he could find a cure for her terminal medical condition in its first season.

And Doctor Who had already used a similar idea - in a Moffat story - when Donna and others were "saved" by the Library mainframe in Silence in the Library / Forest of the Dead.

For the monster, Moffat elected to make this something that the Doctor would be genuinely frightened of, and so made it a childhood nightmare. That it derives from his time on Gallifrey also helps to hint at the conclusion to the episode, where we discover the truth about the castle and who has been responsible for his incarceration.

The Doctor refers to the Brothers Grimm - Jacob (1785 - 1863) and Wilhelm (1786 - 1859) - the German folklorists and collectors of fairy tales. Their 1812 collection Kinder - und Hausmarchen (Children and Household Tales) included The Shepherd Boy.

When the Doctor sends the boy to tell the High Council he's back, he says he "came the long way round" - as the Eleventh stated he would get home in The Day of the Doctor.

After always claiming he had left his home planet due to boredom (The War Games onwards), the Doctor now confesses that he ran away as he was scared.

Next time: From one of the very best episodes ever, to one of the very worst IMHO. It's The Twin Dilemma following The Caves of Androzani all over again. Nice TARDIS though...

Inspirations: Face The Raven

Sarah Dollard was a Melbourne-based fan of Doctor Who who had written for Neighbours and other Australian series, before contributing to the BBC fantasy dramas Merlin and Being Human.

Her inspiration for this story began when a friend explained to her about Trap Streets. These were small non-existent thoroughfares added to maps by their makers to catch out cartographical copyists - as the only way the street could appear on any other map was if it had been plagiarised.

Dollard envisioned these streets as being real, but unknown to the general public. As such they could offer sanctuary to a group of people. It was Steven Moffat who suggested that these may be alien refugees. The idea that the Doctor and Clara might investigate a murder in one of these zones also came from the showrunner.

In order to get the Doctor and Clara into the mystery quickly, the script editor suggested reusing an established character, and graffiti artist Rigsy from Flatline was hit upon. In that story he had mentioned a mother living in London so it was decided that he had located there from Bristol, and he would be accused of a crime he did not commit - providing the motive for the TARDIS pair to get involved. The episode would therefore become a whodunnit.

Dollard then developed the idea that the isolating community had their own unique mode of dispensing justice - a creature which would be released from a cage to kill an individual who had been marked for execution.

This provided a countdown and a fixed timescale in which the Doctor had to come up with the real killer, so a race against time.

The entrance to the Trap Street was originally going to be through the door of a mural Rigsy had painted of the TARDIS. The Mayor was going to be a beetle-like alien, whose deputy was a Sontaran.

Once the episode was moved to tenth position in the series, leading into the finale, it was later decided to introduce the new character Ashildr / Me into Dollard's story as she played a role in the final episode. She then took on the role of Mayor.

Having already stayed on much longer than anticipated, this would be Jenna Coleman's last series. Moffat debated with himself having her leave in the finale or - for shock value - having her killed off earlier. (In the end, he would manage both).

It would be made clear that her death wasn't some form of self-sacrifice. Rather, she died due to her over-confidence and increasing lust for danger and excitement - a belief that she could match the Doctor's abilities. Me would not be held responsible and the Doctor would not be vengeful.

The raven features in many mythologies. 

Odin is also known as the Raven God. He had two pet birds which gathered intelligence for him and acted as spies.

In the indigenous cultures of the Pacific Northwest the bird is both a trickster and a bringer of light to the world.

Celtic mythology has them birds of ill omen, especially when it comes to battle.

The ancient Greeks held that they were servants of Apollo, and were originally white. Apollo singed them in a rage after they brought him bad news.

The design of the Trap Street was based on narrow lanes off Oxford Street in London, and The Shambles in York. Many have noted a similarity to Diagon Alley in the Harry Potter films though Dollard has said that this wasn't intentional.

Among the aliens we see in the street are a Cyberman, Ood and Sontaran.

Among returning guest artists are Robin Soans as "Chronolock Guy". He had played Consul Luvic in The Keeper of Traken. Me's deputy, Rump, is Simon Paisley Day who, as Simon Day, played the Steward on Platform One in The End of the World.

Next time: the Doctor gets caught up in the works and takes a very long time to extricate himself, in what many regard as one of the greatest Doctor Who episodes of all time...

Inspirations: Sleep No More

The episode title comes from Shakespeare - Macbeth Act 2 Scene 2: "Sleep No more / Macbeth does murder sleep".

Mark Gatiss had first thought about a story revolving around sleep in 2010, after suffering a bout of insomnia. The substance we call "sleep" - medically rheum - is a collection of organic material, including dust, skin, mucus and oil, which is produced by way of the eye cleansing itself overnight.

Gatiss was later shown an article about compressed sleep - becoming popular in the business world. Workers were reducing the amount of sleep they took to increase the number of hours they could use for work. The intention was to increase productivity but, of course, led to reduced efficiency through tiredness.

Gatiss thought of a future in which sleep could be artificially compressed so workers could be employed for all but a few minutes each day.

Knowing that Steven Moffat was looking to have more two-parters in Series 9, Gatiss' original idea was in this format, and included conflict between two factions - one which promoted this process and the other which argued for the natural way of things. They were known as the 'Wideys' - for Wide Awake - and the 'Rips' - for Rip Van Winkle.

Rip Van Winkle was the protagonist of an 1819 Washington Irving tale a Dutch-American who fell asleep for 20 years. He returns home to find his wife now dead, his daughter grown, and the old colonial America overtaken by the Revolution.

The process by which sleep was compressed would lead to the rapid growth of the creatures made from rheum, which Gatiss named Sandmen. The Sandman derives from German and Scandinavian folklore - a figure who sprinkles magical sand on the eyes of children to induce sleep and dreams. Rheum is a sign that you had been visited by him. Generally regarded as a benevolent character, ETA Hoffmann wrote a tale in which they were a more sinister figure (Der Sandmann, 1816).

The Doctor objects to Clara naming the creatures Sandmen, claiming "It's the Silurians all over again" - a reference to humans misnaming creatures.

The 1954 release of the song Mr Sandman by The Chordettes features in the episode as the jingle played by the Morpheus Pods. Morpheus was the Greek god of dreams, son of the sleep god Hypnos.

A working title for the episode was "The Arms of Morpheus".

This particular version of the song was originally going to feature as the alien "earworm" in an earlier Gatiss story - the one which eventually developed into The Idiot's Lantern.

Gatiss was happy to have a futuristic setting, as his earlier contributions to the series had tended to be historical in nature. The setting is a space station orbiting the planet Neptune. This had never featured in the series before, and its inclusion was inspired by a Horizon programme Gatiss had watched about the Voyager mission.

The station is named the Le Verrier. Urbain Le Verrier (1811 - 1877) was the French astronomer and mathematician who in 1846 correctly predicted the existence and location of Neptune purely through mathematics, explaining a discrepancy in the orbit of Uranus.

The role of Rassmussen was written specifically for Reece Shearsmith. He was one of The League of Gentlemen, along with Gatiss and Steve Pemberton, who had already appeared in Silence in the Library / Forest of the Dead. He had appeared briefly as Patrick Troughton in Gatiss' An Adventure in Space and Time in 2013.

In the episode, Japan and India have formed a new superpower following "The Great Catastrophe". Gatiss had recently visited both countries, and the latter is a reference to the 1984 story Frontios.

In terms of how the story is presented, as opposed to the plot, then this is Doctor Who's attempt at the "found-footage" style. This became all the rage, especially in the Horror genre, following the success of The Blair Witch Project. This 1999 movie was presented as though it were genuine camcorder footage from a party of three film school students making a documentary about the Blair Witch. They travel to rural Maryland in search of the story, learning of a local 1941 serial killer on their travels.

The entire film consists of their raw documentary recordings, supposedly found after they vanished in the area.

The style became hugely popular with low budget film-makers, though a big sci-fi blockbuster also employed it - JJ Abrams' Cloverfield (2008), directed by Matt Reeves. This depicted the attack on New York by a massive monster (plus some smaller creatures in the subway tunnels).

The problem with the style is that it became overused - especially by those cheap productions. The other problem is how unrealistic they are, despite the whole point being that they're supposed to look as if they are genuine recordings. People running for their lives simply would not keep filming monsters or zombies snapping at their heels.

By the time this story came along the style had fallen out of fashion, replaced by the more static CCTV / home security camera set-up, as seen in the Paranormal Activity franchise.

The ending is odd for Doctor Who at this time, with the Doctor never actually neutralising the threat. This had happened in the programme in some of the historical stories of its earlier days, when the Doctor and companions simply fled the setting in the TARDIS, leaving events to unfold and with some villains undefeated (most notably Tlotoxl in The Aztecs).

Things were left open-ended here purely because a sequel was planned. However, the episode proved unpopular and Moffat was planning his exit from the series anyway - and Gatiss intended to step away from it with him. He wrote Empress of Mars instead - a story he wanted to write whilst he still had the chance.

Next time: The Doctor gets caught in a trap within a Trap, and Clara gets the bird...

Inspirations: The Zygon Invasion / The Zygon Inversion

Another proper two-part story for Series 9, this acts as a direct sequel to the 50th Anniversary story The Day of the Doctor. Indeed, the first episode begins with a recap of events in that story, in which Zygon refugees are forced into an uneasy truce with UNIT thanks to the combined efforts of three incarnations of the Doctor.

As the whole 'Zygons seeking a new home' plot had first been mentioned in Terror of the Zygons, it can be argued that it is a sequel to that 1975 story also.

The 50th Anniversary story had told how the Zygons had arrived in Tudor times (even though Broton had stated that it would take time for their fleet to reach Earth, and he was saying this in the late 20th Century). The Zygons had used stasis cubes to hide themselves in a number of artworks which ended up in the National Gallery. On emerging in 2013 they attempted to take over but the Doctors forced them to negotiate a truce with Kate Stewart of UNIT, whereby they could live in peace on Earth in human form, they being shape-shifters of course.

This new story picks up some time later, when a radical faction of young Zygons are rebelling against the current arrangement. They wish to live as Zygons and not hide, even though both species have co-existed happily for a couple of years.

This radicalisation points to one of the main inspirations for the story. Issues of immigration, integration and the status of refugees also background the episodes.

Interestingly, Steven Moffat always intended to revisit these themes with a global political thriller following The Day of the Doctor - so the Zygon element was always intended as a sort of prequel to a story which would come later, with the Twelfth Doctor following up on something initiated by his predecessor.

The title of the first episode might feature the word "Invasion", but Moffat and writer Peter Harness sought to look at how conflicts started, growing out of dissent from within a community - be it the power vacuum resulting from regime change in countries such as Iraq, or popular revolutions such as the Arab Spring movement.

In recent years we had seen the rise of Islamic State, which had already had an impact on Doctor Who when changes were made to the ending of Robot of Sherwood. Hundreds of young Westerners had flocked to the Middle East to join the movement, and the UK and other European countries had seen a rise in domestic terrorism.

As mentioned, Zygons are shape-shifters, and so Harness was also inspired by that 1950's classic piece of anti-communism paranoia Invasion of the Body Snatchers. Anyone could be a Zygon duplicate.

Kate visits the town of Truth or Consequences in New Mexico. This used to be called Hot Springs but changed its name in 1950 to that of a popular radio game show. The presenter, Ralph Edwards, had announced that the forthcoming 10th anniversary show would be broadcast from the first town to change its name. Once renamed, it never changed back.

Harness originally set part of the story in Azerbaijan, but this became the fictional Turmezistan.

In draft scripts UNIT had characters named Bell and Bambera, but there was no indication that they would have anything to do with previously established UNIT staff Corporal Bell and Brigadier Bambera, so may simply have been placeholder names.

Complaining of shortages, Kate mentioned Sergeant Benton as one of "only about 6 men" her father had to command in his day. (Many of us much preferred the "Brig's Army" to the version of UNIT seen these days).

Once again the Doctor finds himself acting President of Earth, with a special aircraft at his disposal (as in Death in Heaven. Once again it contains a portrait of the Brigadier - based on a publicity photo from Battlefield. And once again, the 'plane is brought down.

The Union Jack parachute is clearly inspired by Bond's in the precredit sequence of The Spy Who Loved Me (1977).

The Doctor mentions having once snogged a Zygon - referring to the one which copied Queen Elizabeth in The Day of the Doctor.

The two boxes in the Black Archive are said to be work of Harry Sullivan. His last story as a regular companion was Terror of the Zygons, and he was said to be working at Porton Down (the UK Government's biological research establishment) in Mawdryn Undead.

One of this series' story arcs has revolved around the notion of a hybrid. The Doctor describes Osgood as a hybrid, in that no-one knows if she was human or Zygon.

Kate orders "five rounds rapid" against a Zygon - part of the famous quote from her father in The Daemons.

Next time: Deadly slumbers. Doctor Who finally does "Found Footage", only 16 years after it became popular, and it is the audience who were mostly asleep during this one...