‘Gallifrey Falls No More.’ I watched this in NFT1 at the BFI with an audience including Sir John Hurt before wandering round the corner to watch them recording the surreal Afterparty. It was the capstone to an incredible anniversary weekend which started with An Adventure in Space and Time and included a trip to the Doctor Who event at the ExCel. The audience response was tremendous, particularly the gasp that went up when Tom Baker’s voice declared, ‘You know, I really think you might.’ It’s as good an anniversary celebration as The Five Doctors, which is the highest praise I can give.

Obviously, at the time and since, I’ve bemoaned the absence of Eccleston – which Moffat surely felt as well given how rooted this is in Series One’s post-war angst (he’s included via a clip and the War Doctor’s regeneration, and Billie Piper stands in as the link back to 2005 like Carole Ann Ford stood in for the Hartnell years in 1983). You couldn’t ask for a greater understudy than John Hurt, who adds not only some star power but incredible gravitas to the decision that has haunted all his later lives. Even the conceit, while born of desperation, makes sense: the life the Doctor wants to forget. The script is simpler and more accessible than some of Moffat’s regular episodes; the scale is bigger than anything the show’s done to date. It’s a superb celebration – with an eye (and two eyebrows) to the future as the next Doctor briefly pitches in.

My favourite bits are: the Zygons hiding in plain sight (Moffat’s favourite) as statues; the tenth Doctor’s mini adventure with Elizabeth Tudor; Kate Stewart’s terrible decision (London or the world) as a microcosm of the Doctor’s own Gallifrey or the Universe; Billie Piper’s performance as she gently guides the War Doctor to his choice, and the silence that falls as the three Doctors contemplate genocide. Clara is now a teacher, but this might easily just be a different splinter than the one that babysits (and now played by Jenna Coleman). Practically the only thing I don’t like is Tennant’s hair – but even that feels like a Five Doctors tradition.

Does the Doctor actually change history? On the surface, it seems clear he does. When faced with the choice of using the Moment again he even says, ‘We change history all the time. I’m suggesting far worse… I’ve changed my mind.’ The Moment tells the War Doctor, ‘They think their future is real. They don’t know it’s still up to you’ in the context of the tenth Doctor asking, ‘For once I would like to know where I’m going’ and the eleventh Doctor knowing the answer is Trenzalore, where he dies. All this suggests that before The Day of the Doctor the War Doctor did, indeed, use the Moment; Gallifrey burned (the tenth Doctor remembers, ‘I’ve seen that’); the Time Lords died and, at the end, there was no-one waiting behind Amy’s crack to save the Doctor when his regenerations ran out.

But… Moffat has also spent a year telling us history doesn’t change, it’s just we’ve been looking at it wrong. And the problem with suggesting history changed here is – if the Time Lords weren’t always asking ‘Doctor who?’ from their pocket universe, why were the Silence formed and what triggered the fatal Battle of Trenzalore? That means the Doctor never destroyed Gallifrey, he just thought he did – ‘I won’t remember that I tried to save Gallifrey rather than burn it.’ The RTD years were built on a lie, the ninth Doctor had no need of survivor’s guilt. The Time Lords were happily saved all the time. The Doctor only died on Trenzalore in the corrupted timeline of the Great Intelligence, where every one of his successes was turned to failure.

Either way, given how large Trenzalore still looms in the Doctor’s future, it’s a mystery in need of a satisfying answer – the success or failure of Moffat’s eleventh Doctor arc depends on what comes next…

Next Time: The Time of the Doctor