‘Can you change back?’ A charming bridge between The Parting of the Ways and The Christmas Invasion which serves mainly to trail the new Doctor. He’s faster, spikier, full of energy, darting about while the last version might have been watchful and, in a sort of safe version of the fifth regeneration, has a manic episode that puts Rose in danger as they speed back towards 2006 Earth and Christmas Day.

In the process Rose becomes, for pretty much the last time, the show’s audience identification figure as she’s initially untrusting, even hostile towards this strange, mockney interloper. Piper’s performance, half hiding behind one of the TARDIS columns as she tries to process what’s happening, sells this. RTD shows he’s totally in tune with the audience: we don’t want the companion to forget about the old Doctor and immediately like their replacement; he has to earn her – and our – trust.

To prove his credentials, the new Doctor pulls on recent memories of the previous series, describing his very first meeting with Rose. I love the way it elevates this moment to a mythical origin story moment, sort of eulogising the ninth Doctor without needing to be sentimental about it. But wisely, this isn’t all reflection and mistrust: the new Doctor is funny, silly (hopping around the console) and a bit mad. ‘I can’t stop myself,’ he says at one point: it’s supposed to be a symptom of the regeneration going wrong, but it could be his byline. Donna knows it. So does Adelaide. And so, soon, will we.

Next Time: The Christmas Invasion