Twice Upon a Time: The Fact File
The adventure opens with a recap and partial retelling of The Tenth Planet, the story which introduced the Cybermen and saw the First Doctor regenerate. We see his two companions from that era – Polly and Ben – originally played by Michael Craze and Anneke Wills, but here (in the recreated scenes) portrayed by Lily Travers and Jared Garfield.

Part four of The Tenth Planet is a ‘missing episode’, no longer in the BBC archives. However, the sequence where the Doctor regenerates (as seen towards the end of Twice Upon a Time) remains available as it was used as a clip in Blue Peter, and luckily the edition it featured in survived!
David Bradley played William Hartnell (the original First Doctor) in An Adventure in Space and Time, written by Mark Gatiss who plays the Captain in this episode. David has also appeared in Doctor Who twice before – as Solomon in Dinosaurs on a Spaceship and, of course, in The Doctor Falls when he made his debut as the Time Lord.
Mark Gatiss first appeared in Doctor Who in 2007, playing the eponymous professor in The Lazarus Experiment. He also starred as Gantok in The Wedding of River Song and ‘Danny Boy’ in both Victory of the Daleks and A Good Man Goes to War. And, of course, Mark has written many great episodes including The Crimson Horror and Empress of Mars.
The German soldier who the Captain speaks to and later assists is played by Toby Whithouse who wrote School Reunion, The Vampires of Venice, The God Complex, A Town Called Mercy, Under the Lake / Before the Flood and most recently, The Lie of the Land.

And Nikki Amuka-Bird who plays ‘The Glass Woman’ portrayed Beth Halloran in Sleeper, the second episode of the second series of Torchwood.
Towards the end of the episode it’s revealed that the Captain is actually Captain Lethbridge-Stewart. If that surname feels familiar, it was the name of one of the Doctor’s closest friends – Alistair Gordon Lethbridge-Stewart. The Time Lord first met that character in the Second Doctor adventure The Web of Fear and was later introduced to his daughter, Kate, in The Power of Three.
The moment where the Doctor asks the Cyberman, ‘Have you no emotions, sir?’ comes from The Tenth Planet but was again seen in Earthshock. The Cyber Leader in that story plays the scene to illustrate what a thorn in their side the Time Lord has always been!
The Dalek the Time Lord calls Rusty was introduced in the Twelfth Doctor’s second story – Into the Dalek. In that episode Rusty’s final words to the Doctor are, ‘I am not a good Dalek. You are a good Dalek.’ Ironically, this is the first line Rusty speaks in Twice Upon a Time.
When Bill tells the Doctor he must ‘serve at the pleasure of the human race’, she’s quoting his own words back at him. In Thin Ice, he revealed he must allow Bill do make the decision about the creature in the Thames, explaining, ‘…it can’t be up to me. Your people. Your planet. I serve at the pleasure of the human race and right now that’s you. Give me an order!’
The Doctor calls the First Doctor, ‘Mr Pastry’, an accident-prone comic character played by Richard Hearne (1908 –1979). You can read more about Mr Pastry’s link with Doctor Who in this Archive feature.

If Twice Upon a Time has aroused your curiosity about the Christmas Armistice of 1914, you can read more about this remarkable moment in history in this BBC iWonder Guide.
When the First Doctor operates the TARDIS we glimpse a name, on tape, fixed to the console: Bernard Wilkie. Born March, 1920, Wilkie was a visionary visual effects designer on several early Doctor Who stories. He also worked on a number of other seminal BBC series including Quatermass II and Quatermass and the Pit.
‘What is anyone supposed to be except a bunch of memories?’ Bill’s line echoes one of the Doctor’s, spoken in The Five Doctors when he noted, ‘A man is the sum of his memories… A Time Lord even more so.’
The Doctor’s line about children being able to hear his name under certain circumstances echoes the words of Peter Capaldi himself. In April, 2017 he was asked by a young fan what the Time Lord’s real name is. ‘I don’t think human beings could even really say his name,’ he replied. ‘But I think we might be able to hear it. At a certain frequency. If the stars are in the right place, and you heart’s in the right place, you’ll hear it.’
And in his final speech, the Time Lord states that the Doctor should never be cruel and never cowardly. We’ve heard this before (in The Day of the Doctor, for example) and it’s an oft-repeated principal of the character. The summing up first appeared in The Making of Doctor Who and was written by one of the show’s greatest contributors, writer and script editor, Terrance Dicks: ‘He never gives in, and never gives up, however overwhelming the odds against him. The Doctor believes in good and fights evil. Though often caught up in violent situations, he is a man of peace. He is never cruel or cowardly.’