Radio Times at Christmas

My Santa is cross, mean and curt as well as cheery and funny. He's got a little bit of Robert De Niro in Mean Streets. And he has history with the Doctor: it's not talked about explicitly but they have a beef with each other from way back.

Steven Moffat is a very clever man - taking Doctor Who somewhere completely different isn't easy. And he was happy to allow me to improvise on set and push things out a bit.

It does look like the most insane moment when Santa turns up, but we haven't gone off our rockers. No, Santa is written in properly, in a science-fiction way, into Doctor Who. I've always had a very clear impression of Santa, but when we got Nick Frost, well, first of all how perfect is his name! Nicholas Frost. It's the nom de plume that Santa Claus would use, isn't it? Nick is ideal. He's what Santa should be in Doctor Who land.

What’s now shocking is I can’t say anything publicly without it having a life. Not because I have extraordinary views but because people are keen on conflict, so they’ll make that the story. They love to make out that Steven Moffat and I have disagreements. But that’s business as usual. It made me realise how awful it must be to be a politician. I’m a lot more sympathetic to Malcolm Tucker’s views now.

That was extraordinary. People tell you the show’s successful abroad but until you actually see it, you don’t realise. You’re effectively joining a boy band or the Beatles. You arrive at the airport and there are packs of people screaming and holding up pictures of you. We’d do press events all day and then in the evening a public screening and Q&A, and people went bananas. In South Korea the venue seated 1,500 people, and 50,000 people applied for tickets. I was benefitting from Chris Eccleston, David Tennant and Matt Smith making the show so beloved – I swept in on their coat-tails and got all the adoration and BA first-class treatment.