15th Doctor - new costume

The BBC have released an image of Ncuti Gatwa in his new costume. It's a very conventional ensemble, in a dark brown tartan tweed. The pullover adds a splash of stronger colour, and perhaps this may change from story to story. Interestingly, all the fan art I've seen since his casting has put him in much more flamboyant clothing, with people influenced by his own wardrobe and how he dresses in other performances.

Countdown to 60: What's two years among friends?

London: 1965!

The fifth significant moment is another Dalek-related departure. In the early days, all of the significant moments in Doctor Who were reserved for the Doctor's encounters with Daleks.

Part Six of The Chase sees the departures of school-teachers Ian Chesterton and Barbara Wright. As with Susan's leaving, this is no ordinary companion departure, however. The entire series up to this point has been the tale of the Doctor attempting to get Ian and Barbara back home to present day London. We've basically been watching a two season-long story arc. If the programme can be divided up into phases (be it based on Doctors, companions, producers or script editors) this instalment marks the end of Phase One.

From this point on, the Doctor simply becomes a wanderer in Space and Time, which will remain the situation until the end of the 1960's.

The photographs of Ian and Barbara running around London, and their bus journey with Derek Ware as the conductor, were the work of Douglas Camfield - director of the story which followed The Chase.

Something which has never been properly explained is just how the teachers got away with disappearing for two whole years. The Day of the Doctor showed that Ian was Chairman of the Board of Governors at Coal Hill School (though they are infiltrated by Weeping Angels just a couple of years later, according to Class). The Sarah Jane Adventures maintained that he and Barbara were academics based in Cambridge. The War Machines novel claims it was through Ian that the Doctor was introduced to Professor Brett (and WOTAN knew his name after hacking his phone line). Ian is on his own at the inaugural meeting of the Companions Support Group.

L is for... Lone Cyberman

When the Doctor's companions - Graham, Ryan and Yaz - encountered Captain Jack Harkness on an alien spaceship, he told them to warn the Doctor about the "Lone Cyberman".

Sometime later they arrived in the Swiss lake regions and the Villa Diodati, which had been rented for the summer by the poet Lord Byron. With him were his physician John Polidori, Mary Wollstonecraft and Miss Clare Clairmont. The villa appeared to be haunted, but it transpired that a substance called the Cyberium was located here, housed in the body of Percy Bysshe Shelley. It was making the house appear haunted as part of a defence mechanism. A shining man had been glimpsed on the lake nearby, and this turned out to be Ashad - a Cyberman who was only partly converted. He had all the ruthlessness of the Cybermen, conjoined with human cunning. The Doctor realised that this was the "Lone Cyberman" whom Jack had warned her about. Ashad wanted the Cyberium - a living metal with artificial intelligence, which would allow him to rule the whole Cyber-race. In the far future the Cybermen were winning the Cyberwar, and the human race was being pushed to the brink of extinction. Ashad revealed that he had killed his own sons when they fought against the Cybermen. He saved the son of Mary and Percy - but only because he expected him to be converted at a later date. Unwilling to allow Shelley to die, and deprive future generations of his work, the Doctor elected to hand the Cyberium over to Ashad, who returned with it to the future.

Feeling responsible for future events the Doctor took her companions to the far future, where they met one of the last refugee groups. They were seeking something called Ko Sharmus, which provided a gateway to a safe zone free of Cybermen. Ashad was here, and he had a scheme to have the Cybermen become creatures totally free of organic components - a purely robotic race. Beyond this he would then wipe out all organic life - leaving only the Cybermen. Whilst pursuing the Doctor, he came across a Cyber-troop carrier, filled with thousands of Cyber-Warriors which he was going to forcibly convert. Ko Sharmus proved to be a person - a general in the human resistance forces and the person who had sent the Cyberium back through time to prevent Ashad obtaining it. He oversaw an energy barrier which led to supposedly safe worlds - one of which turned out to the Gallifrey destroyed by the Master. He was present in the Capitol, and he entered into a deal with Ashad to help him. He would create Cyberman-Time Lord hybrids capable of regeneration. Within Ashad's body was a powerful energy form known as the "Death Particle" which was capable of disintegrating organic matter. The Master used his Tissue Compression Eliminator to kill Ashad, without disturbing the Particle. He also took the Cyberium from Ashad into his own body.

Before fleeing Gallifrey with some Cyber-Masters, the Master had taken Ashad's remains and he later cloned them. He sent this shrunken form to Tegan Jovanka, pretending it was from the Doctor - knowing she would carry it past security into UNIT's new HQ. Ashad had been converted into a Passenger form, containing an army of Cyber-Warriors. Ashad then began converting the UNIT personnel. Tegan and Kate Stewart sabotaged his systems, causing a  feedback which killed the Ashad clone and the Warriors. It also destroyed UNIT HQ.

Played by: Patrick O'Kane. Appearances: The Haunting of Villa Diodati, Ascension of the Cybermen, The Timeless Children (2020), The Power of the Doctor (2022).

• One of the drawbacks of presenting a comprehensive A-Z in sequence for an on-going show, there will always be occasions when I have moved on from a letter before a new character is introduced - which is why Ashad appears here under "L" rather than "A".
• O'Kane featured in Game of Thrones as one of the 'disguises' adopted by the assassin Jaqen.
• He was a First Order commander in Star Wars: The Last Jedi.

L is for... Lon

Spoilt teenage son of the Federator, who oversaw a federation of three planets which included the world of Manussa. This had previously been home to the Sumaran Empire, out of which had grown the evil Mara. Lon's ancestor had defeated them, and coming up was a celebration of this historical event. He and his mother Tanha were visiting Manussa as guests of Ambril, Director of Antiquities.

However, many Manussans had lost interest in their own history, believing the Mara to be a myth. Having previously been taken over by the creatures on the Kinda planet, the Mara resumed control over Tegan Jovanka and forced her to bring the TARDIS to Manussa. Requiring a special crystal from the city museum, Tegan infected Lon in order that he would order its release. At the re-enactment ceremony, this crystal would be used to bring the Mara back. Under the Mara influence, Lon had the Doctor and Nyssa locked up to prevent their interference. He and Tegan also took over a fairground barker to act as a servant. Ambril was blackmailed into releasing the crystal. As the Mara attempted to return during the ceremony, the Doctor tapped the powers of the planet's Snakedancers to fight against them. Once Tegan was freed, Lon was released and the Mara ejected.

Played by: Martin Clunes. Appearances: Snakedance (1983).

• Clunes is the son of actor Alec Clunes, and is related to Sherlock Holmes actor Jeremy Brett.
• He is best known for the long-running series Doc Martin, but first came to fame in the sitcom Men Behaving Badly.
• Despite starting his TV career with the BBC, he has a golden handcuff deal with ITV, presenting documentaries (wildlife / travelogues) as well as featuring in drama productions.
• His embarrassing ceremonial costume in Part Four of Snakedance is often shown on TV in those "before they were famous" programmes - making it one of the most widely seen Doctor Who clips of all time.
• "Lon" is a Spanish name, meaning "noble" or "ready". It is the diminutive of Alonzo.

L is for... Logopolitans

A race of seemingly elderly men who lived on the planet Logopolis, led by a man named the Monitor. They were famous for being able to manipulate Space / Time events through the power of pure mathematics - a process known as Block Transfer Computation. The Doctor decided to visit the Logopolitans to seek their help in repairing the Chameleon Circuit of his TARDIS, worried that it drew attention to itself and to him. He took measurements of a real Earth Police Box and brought them to the Monitor, who would have his people carry out the necessary Computations. He was surprised to see a large radio-telescope overlooking the settlement, as the Logopolitans generally shunned technology. The Master had stowed away in the TARDIS in his own ship, and he sabotaged the Computations, causing the TARDIS to shrink. This was merely a distraction as he then caused disruption in the Logopolitans' on-going calculations. The Monitor was horrified, as Logopolis was keeping the entire Universe alive, bringing in energy from pocket dimensions such as E-Space. Without this, it would have long ago been destroyed. The Logopolitans and their world crumbled to dust - the result of rampant entropy. The Doctor and Master were forced to co-operate to run the Monitor's program from the Pharos Project on Earth - the model for their radio-telescope.

Played by: John Fraser (Monitor), Appearances: Logopolis (1981).

• The Logopolitan costumes were a reuse of the Argolin ones from the beginning of the Season.
• As with Login in Full Circle, Christopher H Bidmead used a computing term to name the Monitor.
• Among those considered for the part of the Monitor were Peter Cushing, Peter Wyngarde, Bernard Archard, Maurice Denham, Harry Andrews, Frank Finlay, Barry Foster, Marius Goering, Michael Gough, Frank Windsor, William Lucas and Nigel Stock.
• Logopolis means "City of words or speech". It can also derive from "the Word of God", as in creative order. 
• From above, the city was meant to look like a gigantic brain - symbolic of their refusal not to employ technology.

L is for... Login

Login was a respected member of the Starliner community on the planet Alzarius. His daughter, Keara, however, was a member of a rebellious group of teenagers known as the Outlers, who lived in a cave overlooking the Starliner. When a period known as Mistfall arrived - when the atmosphere was supposed to turn toxic and monsters roamed the land, the spacecraft was sealed. Login accepted that his daughter was now lost to him. His loyalty to his community was such that when one of the ruling Deciders failed to return to the Starliner, the others - Nefred and Garif - offered him the vacant position, which he accepted. When he learned that the Doctor had managed to break in, and the swamp mists were not poisonous, Login hoped to get Keara back. As it was, a young man named Adric accidentally transported the Outlers into the vessel in the TARDIS. Login showed more interest in the Mistfall phenomenon than his colleagues, wishing to understand what was happening. He helped flood the Starliner with oxygen to force the invading Marshmen out into the swamps. The Doctor then showed him and his colleagues how to operate the Starliner so they could travel to a new home.

Played by: George Baker. Appearances: Full Circle (1980).

• Baker was best known for his regular TV appearances as Inspector Wexford in The Ruth Rendall Mysteries.
• Another significant role was that of the Emperor Tiberius in I, Claudius, and he was also one of the Number 2's in The Prisoner.
• Whilst the producers favoured Cary Grant, Ian Fleming wanted Baker to play James Bond in Dr. No. He appeared in three of the films - You Only Live Twice, On Her Majesty's Secret Service, and The Spy Who Loved Me. 
• He was later considered for a couple of roles in Season 22 - George Stephenson and the assassin Orcini.
• Script Editor Christopher H Bidmead liked to use computer terminology. Login's name simply derives from "log in".

L is for... Logan, Lieutenant General

Commander of British forces in the Sevastapol region of the Crimea, during their conflict with the Sontaran Empire. This had usurped the Russian Empire after the Sontarans had interfered with history.

Logan permitted Mary Seacole to run her "Hotel" which acted as a social hub and infirmary. She had an injured Sontaran warrior hidden there, which she had to keep from Logan.

Unable to comprehend energy weapons, Logan fought his battles in traditional style - marching his men directly at the enemy. The Doctor tried to warn him against this, but he ignored her and witnessed a massacre. He was able to make it back to the Hotel, where the Doctor proposed an alternative scheme - based on the fact that Sontarans entered a brief hibernation phase whilst they recharged.

The Doctor sought to force a retreat by the Sontarans, but having seen the deaths of so many of his men, Logan sabotaged her efforts. He surrounded the alien ships with explosives then ignited highly flammable gas, blowing up the entire Sontaran fleet.

Played by: Gerald Kyd. Appearances: War of the Sontarans (2021).