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...

Inspirations: The Woman Who Lived

The Woman Who Lived is not so much the second part of The Girl Who Died, despite the title structure, as a sequel - showing what happened to Ashildr after the Viking episode.

In order to save her life alien medical technology has been used, which has rendered her immortal. The Doctor had at least left her a second Mire device, if she wished to provide herself with a fellow immortal to act as a partner.

After a scene-setting sequence in the 17th Century, where the Doctor seeks an alien artefact in England only to find it being stolen by a highwayman, we get to see how Ashildr lived her life up to this point - for the Highwayman is a highwaywoman. Ashildr is now local aristocracy - Lady Me - but has turned to crime for a bit of excitement.

One of the things which the production team wanted from this episode was to show someone travelling through time by the "slow road", comparing it with the Doctor's jackdaw meanderings through history.

This was also designed to be a companion-lite episode as it's about the relationship between the Doctor and Me, so Clara only features at the start and at the end.

We see her in medieval times as she fights at the Battle of Agincourt with Henry V (25th October 1415). She did settle down with a husband and had children at one point, but they all died of the plague. As this episode is set in 1651 it can't be the Great Plague of London, so is probably the Black Death, which arrived in England in June 1348. By December when it abated it had killed between 40 - 60% of the population.

We also see her being accused of witchcraft, presumably because she has taken on the role of wise woman in a small rural community. The ducking stool was in use in England over a very long period, going back to Saxon times. This episode can't relate to the notorious campaign in eastern counties by Matthew Hopkins as that was in the mid 1640's, and she is already an aristocrat by 1651. There was a peak of witchcraft trials after 1562 when new legislation came in, so presumably this event can be placed in that period.

It was writer Catherine Tregenna (the first female writer on the series since 2008's The Poison Sky) who decided on the main historical setting.

1651 saw the climax of the Third Civil War, with the Royalist defeat at hands of the Roundheads at the Battle of Worcester that September, following which Oliver Cromwell established the Protectorate in place of the Monarchy. It was a lawless time and highway robbery and other property crimes flourished.

Lady Me's home is said to be at Hounslow, to the west of London, and Hounslow Heath was notorious for highwaymen as two major roads to the south west of England crossed it.

The most famous fictional female highway robber (apart from Barbara Windsor in Carry On Dick, of course) is also a thrill-seeking aristocrat - Lady Skelton in The Wicked Lady (1945), as played by Margaret Lockwood. This was remade in 1983 with Faye Dunaway in the lead role. It is reputedly based on the life of Katherine Ferrers (1634 - 1660), who terrorised Hertfordshire and was shot dead during one of her robberies.

One female highway robber who is said to exist was Susan Higges, who is mentioned in a ballad from 1640 and is reputed to have had a criminal career spanning two decades. She dressed as a man to commit her robberies in Buckinghamshire. She was the inspiration for Renegade Nell  - the character depicted in the recent Disney+ series. Her career of crime came to end when she murdered a woman who was able to identify her before dying, and she ended her life on the gallows.

Talking of which, Sam Swift is due to meet his end at Tyburn. This was the site of a famous place of execution, close to where Marble Arch stands today at the bottom of the Edgeware Road. Public executions took place here from the 12th to the 18th Centuries, until they moved to the vicinity of prisons such as Newgate. It was from Newgate that many of the condemned would travel to Tyburn, stopping off for the odd flagon of ale as they progressed along Oxford Street. At one point the gallows - the "Tyburn Tree" - comprised a large tripod affair that could accommodate a dozen or so people at a time.

The alien of the episode is Leandro - a leonine being who just happens to come from the planet Delta Leonis. The Latin name for the lion is Panthera Leo. The constellation of Leo derives its name from the Nemean Lion - a mythical beast slain by Hercules as one of his 12 labours. And of course we have the zodiac sign of Leo the Lion (July 23rd - August 22nd). Leos are said to be natural born leaders, but can also be arrogant and stubborn.

The Doctor calls Leandro "Lenny the Lion", referring to the ventriloquist dummy used by British entertainer Terry Hall from 1954 through to the 1980's.

Next time: Clara is beside herself as UNIT and the Zygons play Truth or Dare, in a sequel to the 50th Anniversary story...

Inspirations: The Girl Who Died...

But not The Woman Who Lived...

Steven Moffat said that he was going to change the way viewers thought about two-parters this series, and here we have an example of what he was talking about. Many see this and the following episode as two halves of a single storyline - how Ashildr becomes immortal and what happens when the Doctor has to then confront the consequences of his actions in making her so. 

However, the actual narratives within each episode - the background / plot - have absolutely nothing to do with each other, and the Doctor could have had his follow-up meeting with her - now known as Lady Me - at any point later in the series. Indeed, I said in my review at the time that this might have been preferable. There's no reason whatsoever to follow up on her in the very next episode.

There is also the obvious fact that both of these episodes are written by different people.

This is why I'm going to look at the two separately.

Jamie Mathieson had come up with a number of story ideas - but unfortunately every one of them was already an idea being developed by someone else this year. He was therefore given the starting point of "the Doctor meets Vikings" by Moffat.

His first idea began with the Doctor and Clara already captured by Vikings after a school trip to the island of Lindisfarne, off the Northumbrian coast. With them would be a number of other woman taken from the island. The Valkyrie would descend - female warriors on winged horses - and take all the women on Odin's orders. At the floating city of Valhalla, the female captives - who included Ashildr - would be forced to fight gladiatorial combats. In this version it was women whom the aliens wanted, as part of a breeding experiment to create a hybrid species.

The Doctor captured one of the Valkyrie and discovered that they used alien tech. Odin retaliated by sending the Leviathan to attack the Viking village. Part of the Doctor's plan to defeat the aliens was to tamper with one of the Valkyrie helmets.

Only one or two of these ideas / images would make it through to the episode as broadcast.

Leviathan became the wooden dragon used to frighten the Mire, and the tampering with the helmet is what helps feed the Doctor's imagery through the aliens' psychic link and is manipulated by Ashildr - leading to her death.

Moffat liked the notion that the Doctor had to train a second-class band of Vikings to become an effective defensive force. In this he was inspired by Dad's Army - the much-loved BBC sit-com about the Walmington-on-Sea Home Guard, broadcast between 1968 - 1977. This even led to a working title of "The All Father's Army" - 'All-father' deriving from Norse mythology, another name for their supreme god.

The Doctor would also have to furnish his Viking band with weapons derived from the only available resources and technology - an idea exemplified by US action series such as The A-Team and MacGyver.

Another very obvious inspiration is The Magnificent Seven (1960), which was a Western version of 1954's Seven Samurai. In these a small group of ill-prepared locals have to defend their community against a larger, more organised force, making use of the advice and support of outsiders.

Moffat was quick to point out that he knew that Vikings did not go around in horned helmets all the time. Horned, or winged, helmets were worn only on ceremonial occasions - but were popularised in the 19th Century through productions of Wagner's Der Ring des Nibelungen. 

However, he thought that the general viewing public would expect to see them and they were a good visual shorthand for "Viking".

The Mire were originally intended to be humanoid in appearance, wearing helmets akin to the famous Sutton Hoo one. At one point Vikings were to have been inspired to add horns to their helmets because the Mire wore them on theirs.

Vikings had appeared in the series once before - in The Time Meddler - and John Lucarotti had attempted to contribute another story involving Eric the Red's discovery of the Americas. The Vanir in Terminus are based around Norse mythology, which also feeds into The Curse of Fenric and The Greatest Show in the Galaxy. A later working title for this episode would be "Ragnarok".

Odin was the All-father, or king of the Norse pantheon. He is generally depicted as an older, bearded man with only one eye - having sacrificed the other in order to drink from the Well of Mimir, which gave him great wisdom.

The role, here played by David Schofield, was originally intended for Brian Blessed, who had played the blustering King Yrcanos in Mindwarp, but he had to drop out after taking ill.

This episode takes the time to explain why the Doctor looks exactly like someone he met in a previous incarnation - namely the Pompeiian marble merchant Caecilius. In The Fires of Pompeii, the Doctor had been convinced by Donna Noble to save Caecilius and his family, and here he realises having his features is a sign that he is expected to save others. The Doctor had questioned the familiarity of his new appearance in Deep Breath.

The Doctor demonstrates his skill in communicating with babies once again, having been seen in A Good Man Goes To War and Closing Time.

He is also seen playing with a yo-yo, a toy he has used since The Ark in Space, often for the serious purpose of judging local gravity.

In one of the drafts of this episode, the Doctor was to have taken Ashildr's body to the Sisterhood of Karn to be saved using the Elixir of Life - first introduced in The Brain of Morbius.

At one point the Doctor talks of how he could "reverse the polarity of the neutron flow" - the classic Third Doctor line only ever spoken in full in The Sea Devils, with a later cameo by Pertwee in The Five Doctors. However here the Doctor claims not to know what it actually means.

The Doctor also refers to his 2000 Year Diary. He was earlier seen to have a 500 Year version from The Power of the Daleks onwards.

Next time: a quick jaunt through European medieval and early-modern history, and the Doctor is forced to stand and deliver...

Inspirations: The Magician's Apprentice / The Witch's Familiar

In planning the next series of Doctor Who, Steven Moffat decided to revisit the two-parter format. He had been generally dissatisfied with these, feeling that the only way to do them was to have the second half going off in a new direction - sometimes having little bearing on what went before. He had recently cut back on these, ending Series 6 and 7 with single episode finales.

For this series he thought that they might try some big two-parters which could act as a selling point, as they allowed him to tell bigger stories that might not fit a 45 minute timeframe. How these worked might be different, however, and he was keen to see them used as more than simply two halves of a single storyline.

Rather than end the series on a blockbuster, Moffat also decided to kick the series off with one.

He hadn't written a substantial Dalek story by himself since Asylum of the Daleks, and saw this as the ideal opportunity to have another go. He was keen to experiment further with the notion of Daleks assembling from different eras of the series' history. This led to the setting of Skaro.

Looking back, his favourite Dalek story had been Genesis of the Daleks. Indeed, he thought it one of the best Doctor Who stories ever.

This led him to include Davros in his new story - not seen since Series 4's Journey's End - and he considered a certain sequence in the 1975 story as a powerful inspiration. This is the scene where the Doctor anguishes over destroying the Dalek nursery, and asks his companions if they could kill a child, even knowing it would grow up to be an evil dictator.

This led to the Doctor having the opportunity to kill Davros as a child. Moffat looked back at all the Davros stories and saw how the big confrontations between him and the Doctor worked really well - with the narrative gradually building towards them. He envisaged scenes of the pair debating their respective moral values.

Missy's inclusion did not feature in the initial plans for the story, but Moffat wanted to develop the character further. The Master had worked with the Daleks in the past - in Frontier in Space - so had their own history with them.

The Magician's Apprentice / The Witch's Familiar had two prologues. The one showing the Doctor living with Medieval  characters, constructing a well, was the intended one. The other - in which the Doctor is seen hiding on Karn as Colony Sarff comes looking for him, was actually supposed to be part of the first episode, but was shifted to form a stand-alone prequel.

Sarff is Welsh for "serpent", hinting at his true nature.

Karn was first seen in The Brain of Morbius - a bleak planet  in the same region of the universe as Gallifrey and home to the mystical Sisterhood, who had historic links with the Time Lords. The planet had been revisited briefly in another prequel - Night of the Doctor. Leader of the Sisterhood, Ohila, had also been seen in this.

UNIT use temporal paradoxes to help look for the missing Doctor across Earth's history. They identify a trio of these surrounding Atlantis. This is reference to the three different versions of the fall of the city state, as seen in The Underwater Menace and The Time Monster, and mentioned by Azal in The Daemons. Other locations mentioned include 15th Century San Martino (The Masque of Mandragora) and Troy (The Myth Makers).

Peter Capaldi sent Moffat an email following Series 8, suggesting certain things he'd like to see the Doctor do in the next season. One of these was him playing an electric guitar, and he was surprised Moffat agreed to it.

The Dalek slaves like Bors (a name first used in The Daleks' Master Plan) were introduced in Asylum of the Daleks.

The action moves from Medieval England to Skaro, and we see a city whose design was inspired by the one which featured in The Daleks. The first sight of a Dalek here has the general silver / blue livery of the ones seen in that story, as we know from colour photographs of its production.

Inside are a number of Daleks with different colour schemes, including black domed ones seen in The Evil of the Daleks and gunmetal grey ones first introduced in Day of the Daleks.

In charge is the red / gold Supreme first introduced in The Stolen Earth.

Also present is the Special Weapons Dalek, introduced in Remembrance of the Daleks.

Skaro was said to have been destroyed in Remembrance of the Daleks, but was present in the 1996 TV Movie. The city was last seen, in ruins, in Asylum of the Daleks. It is claimed that the Daleks simply rebuild what they lose, to get round these inconsistencies.

Friends of the Doctor hiding in Dalek casings have been seen in The Daleks and The Planet of the Daleks, and the Doctor himself hid in one in The Space Museum.

The episode titles are a reference to The Sorcerer's Apprentice - the 1897 classical composition by Paul Dukas. This is best known for its inclusion in Disney's Fantasia (1940) - originally intended as a stand-alone piece for Mickey Mouse.

Sarff's search for the Doctor takes in a number of locations seen in the series before - the Maldovarium (The Pandorica Opens) and the Shadow Proclamation (The Stolen Earth). The latter sees the same actress - Kelly Hunter - playing the Shadow Architect, and Judoon are present as before.

In a Star Wars cantina-style bar we see a Sycorax, an Ood, a Hath, a Khaler, a Skullion (from the last of The Sarah Jane Adventures, The Man Who Wasn't There) and a Blowfish (first seen in Torchwood's Kiss Kiss, Bang Bang).

A cultural reference which younger people, and those from outside the UK, would have missed was Missy's declaration that she would speak to UNIT "through the square window". This comes from the classic pre-school children's series Play School (1964 - 1988). Each week viewers were asked to guess through which window - square, round or arched - the next filmed item would appear.

Musical references include Missy's "Oh Missy you so fine..." paraphrased from Toni Basil's 1982 hit Mickey and Mott the Hoople's All The Young Dudes (1972).

Next time: Timey-wimey ghostly goings-on, at the bottom of a lake...

Inspirations: Last Christmas

A fairly straightforward one this, as most of the references are actually spelled out for us on screen...

Before we get into them, the Doctor has previous form with Santa Claus. 

In his Eleventh incarnation he claimed him to be a personal friend, and he knew him as Geoff. He kept a photograph of himself with Geoff and Albert Einstein in his wallet (A Christmas Carol).

The First Doctor - in comic form - encountered Santa in "A Christmas Story", which ran in TV Comic between issues 732 - 735. He and grandchildren John and Gillian helped Santa defeat an evil magician. Santa had been inundated with requests for toy TARDISes.

The episode title derives from the popular Wham! song of the same name, which gets rolled out every festive season since it first appeared in December 1984.

The bulk of the episode is set at a scientific research base in the Arctic. Such a base coming under attack from an alien threat naturally brings The Thing (From Another World) to mind. Based on the novella Who Goes There? by John W Campbell (1938) it was adapted for the cinema in 1951, and later remade by John Carpenter (1982). An inferior prequel / remake was released in 2011.

(The Thing was also a huge influence on the first two episodes of The Seeds of Doom. In the 1951 film, the alien is a plant-based lifeform).

The aliens here are the Dream Crabs, or Kantrofarri. In appearance and mode of attack they closely resemble the Facehuggers which feature in all of the Alien movies, starting with the original in 1979 and going up to 2025's Alien: Earth TV series. 

Possibly the most famous cinematic appearance by Santa Claus (unless you count the so-bad-it's-good Santa Claus Conquers The Martians, once voted the worst movie of all time) is in Miracle on 34th Street. 

This was first filmed in 1947, with Edmund Gwenn playing a department store Santa who claims to be the real thing. It won three Oscars. 

This was also given the remake treatment, in 1994, when Richard Attenborough played the Santa figure, Kris Kringle. One or other version is screened most Christmas times. There is also a 46 minute made-for-TV version from 1955, available on YouTube.

At the end of Last Christmas, when Shona wakes from her dream, we get to see her "To Do" list. It includes watching Alien, The Thing and Miracle on 34th Street... 

She also has a Game of Thrones watch planned. Shona is played by Faye Marsay, who just happened to later feature in the series as the Waif, who torments Arya Stark when she first joins the Faceless Men order. 

(Shona was briefly considered as the new companion, if Jenna Coleman hadn't decided to stay on as she enjoyed working with Capaldi so much).

Michael Troughton is also in the cast - brother of David who featured in the series several times, and son of Patrick, the Second Doctor.

Dan Starkey usually plays Sontarans such as Strax.

The 2010 movie Inception was another inspiration for this episode, in that it features people who can enter the dreams of others.

The Doctor trapped in an environment which may or not be a dream was previously used in Amy's Choice.

Next time: The Doctor goes on the run when Davros remembers (probably because he's been watching old Doctor Who episodes)...

Inspirations: Dark Water / Death in Heaven

Dark Water / Death in Heaven formed the two-part finale to Peter Capaldi's first season, and reintroduced the Master in a new incarnation.

Interestingly, RTD had first retooled the Daleks when he took over, then the Cybermen and then the Master over the course of time - and now Moffat has done the same during his few series in charge: the New Paradigm Daleks in Series 5, the "Iron Man" Cybermen in Series 7, and now a female Master in Series 8.

Those new Cybermen also appear in this. This makes it the fifth time they've turned up in the penultimate episode of a series.

The episode begins with a bit of a shock as semi-regular Danny Pink is killed in a road traffic accident. Clara wants the Doctor to intervene and save him - something which takes us right back to the origins of the series. In The Aztecs, the Doctor tells Barbara that they cannot change history - "not one line!". He doesn't elaborate on why this should be, but does state "believe me, I know" - suggesting he has tried and failed to change something himself, or it is something which was explained to him back on his home planet. There appears to be some sort of law, but whether it is natural or manufactured and imposed isn't explained.

When we get to The Reign of Terror just a couple of months later, we learn that it does indeed seem to be some natural force - as though "Time" itself can intervene. There's talk of how trying to shoot Napoleon would inevitably see every attempt fail. This, of course, contradicts The Aztecs, where the Doctor fears that Barbara really could alter history.

When it comes to the deaths of Katarina and Sara Kingdom, the idea of using the TARDIS to somehow save them isn't even considered.

The next companion death isn't until Adric's in Earthshock and here the Doctor specifically states that he cannot (or will not) change what has happened. (Might just be he's glad to see the back of him, mind you...). Tegan and Nyssa ask him to intervene, and he angrily tells them never to ask him to do anything like that again.

The "deaths" of Amy and Rory are different. Here they have gone back in time and died natural deaths, and there's some business about the TARDIS being unable to visit New York due to all the temporal paradoxes. (What was to stop the Doctor simply landing somewhere else that year and fetching them back by train, car, steamship etc is never explained).

In this story, Clara tries blackmailing the Doctor into changing Danny's fate, and he refuses - though only to see how far she will go to force him. He doesn't try using the TARDIS to go back and stop Danny being run over, however. Instead he decides to use Clara's link to the telepathic circuits to bring the ship to where he now is, which he believes is the Afterlife. 

Which is a long-winded way of getting us to the first big inspiration on show - the myth of Orpheus in the Underworld. Greek myths had formed the basis of Doctor Who stories in the past - especially if Anthony Read was involved. He had script-edited Underworld and written The Horns of Nimon. A Gorgon had also featured in The Mind Robber, as had a Minotaur - creatures which have popped up a few times in the series over the years.

Musician Orpheus is wed to Eurydice, a wood nymph, and one day she is bitten by a viper and dies. He uses his skills to charm Cerberus to get into the Underworld to find her and bring her back. Hades allows this - on the condition that he does not look back but trusts her to follow him. He can't resist a peek just as they are about to leave the domain, and so he loses her forever.

Here, Clara fulfils the Orpheus role - going in search of her lost love. As with the Greek myth, they are reunited only for her to ultimately lose him - Danny electing to free another "soul" from the Afterlife in his place. This is a boy whom he inadvertently killed whilst on active service, and it has been hinted throughout the series that he was suffering from some form of PTSD relating to is time in the army.

It turns out that the Afterlife isn't any sort of spiritual domain, but an artificial one - Gallifreyan technology based on the Matrix (first introduced in The Deadly Assassin, in which the villain is also the Master in a new form). 

Many fans guessed the identity of the mysterious woman who had been turning up throughout the series. Moffat was originally going to call her Misty.

A potential deflection was naming the founder of the 3W institute Dr Skarosa (suggesting a Dalek connection)

Moffat claimed that he had always wanted to write a Cyberman story (the previous ones during his tenure having been written by Gareth Roberts and Neil Gaiman) as they were his favourite monsters.

The image of the Cybermen in their tanks derived from memories of them in their niches on Telos in The Tomb of the Cybermen. 

He wanted a big cinematic story, so a series finale was the obvious choice. He also recognised the fact that these tended to be weak in the second half following a great opener and so decided that the cliff-hanger should see the story go off in a new direction (even though this was often the reason for the failings in the past).

Michelle Gomez had been offered the role of Miss Delphox in Time Heist but had been unavailable, but expressed an interest should anything else come up. Moffat saw the opportunity of matching the Glaswegian Doctor with a Glaswegian Master too good to miss, but elected to do something different with his arch-enemy. He claimed to have struggled to write for a female Master, until Gomez was cast.

It had already been suggested in dialogue that Time Lords could change gender (e.g. the Corsair in The Doctor's Wife) so the Master became the Mistress, or Missy for short.

Doctor Who references abound. 

The main one is the nod to the classic story The Invasion, in which UNIT had battled the Cybermen, with iconic scenes filmed next to St Paul's Cathedral. Kate Stewart even produces a damaged Cyberman helmet from this story.

The institute's name - 3W - might just possibly be a nod to The Wheel in Space, another Cyberman story. The Wheel's call sign begins W3. No? Attentive viewers would have recognised 3W's overlapping big circle / small circle motif as a Cyberman's teardrop eye design. This was first introduced in The Wheel in Space.

We learn that Missy was the woman who gave Clara the Doctor's phone number way back in The Bells of St John.

Clara's birthday is given as 23rd November - the series anniversary.

She has post-it notes on her fridge with "Blinovitch" (which would have referred back to Kill The Moon as Courtney was originally going to be the future Mrs Blinovitch), "Psi", "Vastra", "Saibra", "Robin Hood" and "Dinosaur in London" - all references to Series 8 episodes.

She also has the Hyperspace Body Swap ticket - which had featured in the Doctor Who Prom in 2013.

Pretending to be the Doctor, Clara claims to have been married four times. This would be to River Song, Elizabeth I, Marylin Monroe, and to the grandmother of Susan. (Missy sings "Happy Birthday, Mr President" in the same manner in which Monroe sang to JFK).

The funeral parlour where Danny's body lies is called Chaplet's - as in the surname of the First Doctor's companion Dodo.

Missy gives the co-ordinates of Gallifrey as first stated in Pyramids of Mars (10-0-11-00 by 02, in the constellation of Kasterborous).

Other references include the Cyberman attack on the UNIT aircraft, which comes from the classic 1963 Twilight Zone episode "Nightmare at 20,000 Feet".

The Cybermen emerging from their graves was a direct nod to George Romero's Night of the Living Dead (1968).

Missy descends from the sky holding a parasol - as in Disney's Mary Poppins (1964), and her dress mirrors the magical nanny's.

Missy calls out "Bring out your dead" - which was the cry heard around the streets of London during the Plague of 1665.

Colonel Ahmed and Osgood discuss the similarity of the Valiant to Cloudbase, which featured in Gerry Anderson's Captain Scarlet and the Mysterons, and mention how this is sometimes confused with Thunderbirds.

Next time: The Thing meets Alien meets Miracle on 34th Street meets Santa Claus Conquers the Martians...

Inspirations: In The Forest Of The Night

Writer Frank Cottrell-Boyce had been a fan of Doctor Who for many years, his favourite era being that of the Third Doctor when accompanied by Jo Grant. He liked Earthbound stories where familiar surroundings were invaded by some alien presence.

He once worked with Russell T Davies and had spent some years writing for UK soaps, but his big break came when he was chosen to write the opening ceremony for the London 2012 Olympic Games. Davies recommended him to Steven Moffat and he was asked to submit a story idea for Series 8.

He looked back to the Pertwee era and decided that his episode would see London invaded, but in an unusual way. He opted to have it overrun by trees, as these could neither be dealt with through technology or through negotiation. They were simply wood, which even the sonic screwdriver had no effect on.

The Doctor would be placed in an almost impossible situation as to how to resolve the crisis.

A father of seven and a writer of children's books as well as TV scripts, Cottrell-Boyce decided that kids would play a prominent part - feeling he knew their language well.

A school-trip sleepover seemed like a good starting point.

He also began looking at the forest in fairy tales, where it is often a scary place wherein wolves and witches lurk. Hansel and Gretel and Little Red Riding Hood, for instance, see children threatened in seemingly idyllic forest settings.

(Note how Maebh wears a red coat with a hood).

On waking, Clara initially thinks that the group must have been asleep for 100 years, just like in the original Sleeping Beauty tale La Belle Au Bois Dormant.

The principal child character - Maebh Arden - derives her surname from the Forest of Arden in Warwickshire, close to Shakespeare's home and an inspiration for some of his works such as A Midsummer Night's Dream and the actual setting for As You Like It.

Her first name is Irish, deriving from an ancient warrior queen named Medb. It can mean "she who rules" or "she who intoxicates", as it is related to the word mead - the drink enjoyed by the Doctor in The Time Meddler.

Schoolgirl Ruby was named thus as she was the person who spotted the bright red tree-ring in the museum, alerting the Doctor to the fact that this had happened before.

The episode title comes from William Blakes's 1794 poem The Tyger. The opening lines are "Tyger Tyger, burning bright, In the forests of the night..." - an allusion to the animal's fiery orange coat.

It was only natural that Cottrell-Boyce would then place a tiger in his narrative. With London overrun by trees the cages of the zoo at Regents Park might well have been breached, allowing the animals to escape.

The school sleep-over takes place at the Natural History Museum in South Kensington, and at one point we see Danny, Clara and the children passing a stuffed tiger. Early drafts used the Science Museum as the opening setting.

The other main location is Trafalgar Square, as Nelson's Column provided a tall landmark for characters to aim for and it is regarded as a central point for the city - as well as being useful shorthand for London. The Column rising above the trees reminds us of an image Bob Baker & Dave Martin wished to include in The Sontaran Experiment - itself inspired by astronaut Taylor's finding of the Statue of Liberty at the conclusion of The Planet of the Apes (1968).

At one point the script was going to have Maebh pass on to the Doctor a message from the Here - the little light creatures. This was "You are not alone" - signposting the imminent return of the Master in another incarnation, having first been spoken by the Face of Boe in New Earth.

Moffat decided the reference was too obvious and dropped it. We do see the mysterious woman who has been popping up all series once again - watching the solar flare being deflected by the forests on her tablet.

Next time: UNIT and Cybermen at St Paul's Cathedral - but it's not The Invasion. And yes, the Doctor will discover, once again, that he is not alone...