Steven Moffat: To different degrees, that carries on throughout the series, in different ways. But that’s not an accident, that’s a very explicitly clear idea. I was starting to think there was a danger we were getting faster every year and soon the episodes would be over in four minutes [laughter]. Not that I didn’t like that, I loved the way we did it, but every idea has its end and there has to be a new one.

On how the new Doctor has changed things:

Jenna Coleman: I think the show feels very rejuvenated. It’s thrown everything off kilter and turned it on its head, especially for Clara, because suddenly she’s faced with this man and she can’t figure him out and she can’t control and he doesn’t respond in the same way as she’s used to, so that is really frustrating and confusing for her, how to figure out how this now works because it’s so totally different. It’s been a really interesting story to tell over the series.

[…] Again it’s going from being so safe and comfortable with Matt’s Doctor to somebody who doesn’t even register that she’s a girl, or human for that matter! It’s all these changes and trying to figure out how this is going to work now.

Steven Moffat: The thing about Clara with the Eleventh Doctor was that she was comfortably in control, she really had him quite tame. He was thinking ‘she’s really great and she hangs out with me I’m so cool. I’ll roll over on my back, she’ll tickle my tummy and that will be that’. From the moment Peter’s Doctor turns up she realises she’s in terrible trouble, that he’s just rude to her and whatever he might secretly feel, he’s just being awful. Seeing Clara on the back foot, particularly in this episode, makes her very funny I think. We had the perfect girl and we absolutely messed her head.