Steven Moffat has said that the outline for series 8 is already written. According to Buzzfeed:
“Yes, I’m afraid,” he said, when asked whether he outlined future seasons. “We have to work quite a long way in advance. The next season is plotted out. I always end up complaining about it, but it’s quite fun. I’m just making up nonsensical adventures, what’s wrong with that?”
Flanked by the current Doctor, Matt Smith, and the reigning companion Jenna Coleman, Moffat also reflected on the chain letter nature of the long-running series, which has been passed on from one producer/star team to another for half a century. Has he thought about how long he plans on running the series – the next season will be his fourth – before letting someone else have a crack at pushing and twisting the canon?
“Forever. We’re not letting anyone else do it,” he joked, part of an effort to shy away from talk of a timeline or his legacy. “You take it a year at a time, that’s all you can do. It’s such a commitment. It’s nine or ten months a year of work, so I think you can only really do that a year at a time anyway. And if you start thinking of the legacy now… we’ve got a long time to think about that, when people have forgotten us. We just want it to be great. All I ever worry about is the show that is coming out on Saturday.”
Personally, I’ll just be happy if Smith’s hair grows back before filming…