He also talked a little about the episode, saying:
“I’ve written [one] that broadcasts in May. It guest stars Warwick Davis, Tamzin Outhwaite and Jason Watkins. The episode is called The Last Cyberman. It's about identity, it's about responsibility and it's about porridge.The 'porridge' he's talking about is presumably Warwick Davis' character, called (surprise!) Porridge.
He also talked about his favourite Doctor:
“I think it’s really hard. It used to be Patrick Troughton, because he was my doctor, the one I grew up with. Yet, Matt Smith is amazing, and it’s writing for him that gives me an increased awareness of how amazing [he is]. He is technically one of England’s finest actors. Matt for me is the only Doctor who really feels a thousand years old and a kid – he really is this ancient space alien.”