► Face the Raven, the tenth of 12 episodes in the 2015 series, ended with companion Clara killed and the Doctor teleported away to who-knows-where. The penultimate episode, therefore, needed to feature a grieving Doctor – with showrunner Steven Moffat setting himself the huge challenge of showing the Doctor only (at least, for the most part). Given such a radical proposal, the idea was referred to BBC One controller Charlotte Moore and Head of Drama Commissioning Polly Hill for their approval.
► Following her work on the twopart finale to the 2014 series, Rachel Talalay (right) returned to direct the concluding pair. For the most part, the only actor sharing the screen with Peter Capaldi was movement artiste Jami Reid-Quarrell, previously Colony Sarff in the seasonopening The Magician’s Apprentice/The Witch’s Familiar, as the Doctor’s mute pursuer, Veil.
► The majority of the initially untitled episode was recorded over 16 days between Wednesday 24 June and Friday 24 July, with two days on location required in addition to Roath Lock studio interiors. Cardiff Castle (below right), first used for The Rebel Flesh/ The Almost People (2011), provided various corridors and stairways, plus the ballroom, library and others, while work at Caerphilly Castle, first used for The End of Time (2009-10), included shots of the sea door, the dining room, the hall and various staircases. The closing Gallifrey scene was shot, alongside season finale Hell Bent, on Fuerteventura in the Canary Islands at the end of August. Stuntman Rob Pavey doubled Capaldi in water-tank sequences shot in September.