The 7th Doctor said it during Battlefield, although he was also a huge liar (more so then normal for The Doctor) so who knows if he was telling the truth. He could have been outright lying or stretching the truth.
Don't want to drag the The Doctor Falls thread with this specific plot point, so I'll say it here: I think the Christmas Special will be Moffat's final love letter to the Doctor and state just how NECESSARY regeneration is, by showing the First and Latest Doctors and maybe cameo via clips the rest of them to showcase that. So... there.
As I said in the TDF thread, I don't like how Moff is trying to shape Who history around his vision, it's stultifying. Wish Capaldi was staying for one more year...
That's what every single person in charge of the series, or any TV series for that matter, is employed to do.
I mean that he is deliberately changing things that shouldn't (see Allyn Gibson's reply to my comment in the TDF thread).
What I don't get is that Moffat has previously talked about how the show is about one Doctor and his current adventures as an excuse for why we never get special or TV movie starring a former Doctor. He's also complained about having to write multiple Doctors together was one of the most difficult things about Day of the Doctor. So why is he now choosing to do a two Doctors adventure for his grand finale?
But that carries with it a few more issues. I am going with the popular speculation that from the First Doctor's perspective this takes place at the same time as The Tenth Planet and that the two Doctors are going to help each other deal with their impending regenerations. But if we're getting a team-up with the First Doctor as a parting gift to Capaldi, wouldn't it make much more sense to have it take place at some point when the First Doctor is travelling with Susan, to satisfy another of Capaldi's wishes to do on the show?
They could do both, from the first Doctor's perspective it takes place during The Tenth Planet but there's nothing stopping them from hopping into twelve's Tardis so that One can see Susan one last time before he regenerates.
As I said on the TDF thread, I'm wondering if that's exactly what's going to happen. Either this whole Capaldi is leaving is some sort of 'bait & switch' or 'red herring' ala Torchwood which killed off one of its 'central characters' in the very first episode after building them up in the publicity and promotional pieces as a regular character, or simply that Capaldi changed his mind about leaving/was persuaded to stay another year.
There is another possibility. Capaldi IS leaving, and will be replaced by a woman. The leaked set photos show Pearl Makhie on set and there was a line from Heather the Pilot at the end of the episode that she could be human again if she wants, 'It's just rearranging atoms'. Maybe she chooses that option and continues travelling with the Doctor in the Christmas Special. That would eliminate her fate being a retread of Clara's. And with the new Doctor being a woman, and possibly a young(ish) one at that and given that Bill is lesbian you could well have a situation where they bring back the dynamic between the 10th Doctor(11th counting the War Doctor) and Rose, and to a certain extent Martha.
The BBC Charter forbids lying to the audience. Since Capaldi's departure has been officially reported by the BBC, it is happening. That simple, really. The situation with Suzie on Torchwood is a bit different, since the actress was listed in the main cast for the first episode, it counted as obligations met.
Yeah, who was it? Phoebe Waller-Bridge? Kate Winslett? Gillian Anderson? I'm still hoping for Amara Karan... Oh, no. Don't tell me it's Billie Piper!
I'm pretty certain that particular directive in the charter doesn't preclude misdirecting the audience to avoid spoilers.
Yeah but the Moff and numerous other people in the biz fudge truths or lie to cover up what fanbases take potshot guesses at and manage to get right... show makers 50 years ago didn't have such headaches to deal with.
Capaldi under the reins of Chibnall as producer would be interesting. But it seems not to be. The Moff's only real problems have been having to change his arcs' complexity, the delays between seasons that only make the attempt to be more complex fall that much more apart since only initial viewing and ratings therein matter, and - of course - the jokey moments that are more often unfunny and do more to drag down whatever his vision wants to be. He's still brought a lot to the show, but I wish Capaldi hadn't become Mr Funny Man like Smith and Tennant were doing. Smith was the funniest and felt most natural of the modern Doctors incorporating humor, at least early on...