I might go back in time to the past and see if I could infiltrate the upper echelons of the BBC and reverse one or two decisions that one may not have agreed with – let’s not be more specific than that. That would be kind of tempting, wouldn’t it?

And I’d like to go to one or two casting sessions and be standing by the director when he casts somebody in a part that I wanted, and say to him ‘Have you ever thought of Colin Baker?’

But that aside I love the whole thing of time paradox because when it comes down to it in any Doctor Who story, if things are going badly, the Doctor can nip into the TARDIS, go back half an hour and do something different. Very often we kind of gloss over that because it would make it too easy, but in this story that we’re doing now we actually do engage the whole question of time paradox and I think it’s a brave story for that.

If I was a good enough writer to write a Doctor Who story, and you’ve got to be a pretty good writer to write one, I’d want to investigate all those possibilities.