A whole stripey-scarf wearing, blue box adoring fandom is holding its breath as it prepares for the new series of Doctor Who to land on August 23.

One of the men behind the cult show, Islington writer and actor Mark Gatiss, talks to us about the new Doctor, Crouch End resident Peter Capaldi, and when his other cult show Sherlock, which he writes and stars in, will be back on our screens.

What are you up to this morning?

I’m out having a run. I’m just standing in a playing field that’s covered in those laughing gas cylinders we’re hearing so much about, isn’t that frightening?

Are you looking forward to the new Doctor Who?

Yes, enormously. I’m actually going to New York for the BBC America launch, so that’s nice. Yes, it’s wonderful. My episode is number three and Peter Capaldi’s absolutely sensational, it’s very, very exciting. It’s just such a strange thing, as a life-long Doctor Who fan. I remember when Peter Davison was cast and everyone said ‘How can the Doctor be that young?’ and now, since the show came back, particularly with David and Matt, the Doctors have been so much younger and now people are going ‘Well the Doctor can’t possibly be in his 50s’! The entire world has been turned upside down! But it’s a very exciting thing now because suddenly the radical thing is to make the Doctor look more like he did when we were kids! Which is really strange!

Does it make a difference, who the actor is, when you’re writing it?

Oh, yes. The Doctor’s always the Doctor, you have to remember that. What often happens, I’ve done this ever since ten years ago when it started filming again, which is incredible, but I’ve done it at every script reading when the Doctor hasn’t been cast yet, you sort of do the Doctor and then, as you know who’s cast and you start to watch things they’ve done or you know them already or whatever, you start to apply their sort of speech patterns. And then Steve Moffat often sends me his first script and says, ‘This is the sort of thing I want it to be like’. It’s an evolving process, really.

And you’re recognised more for Sherlock than the Doctor?

I mean the Doctor’s already a global phenomenon, but for Sherlock to assume the status it has after only nine episodes over four years!

When is the next Sherlock series going to be filmed/aired?

We doing four this time, we’re doing a special which we film in January and then we’re doing three more episodes later in the year. They’ll hopefully all be on in 2016, so it’ll be a traditional two-year wait, but there will be four of them this time, so it’s a bonus! People go ‘I cannot wait’ but it’s always two years! It’s never any quicker. It’s increasingly difficult, you see, to get everyone together, even though they’re very willing, it’s very hard to get diaries to align when you’ve accidentally cast two superstars!

Were you surprised at just how popular it’s become?

We were very confident and very pleased that we’d made a good show, because Steve Moffat and I, you know, we’re absolutely dyed-in-the-blood Sherlock Holmes fans, so it was a huge labour of love for us to do our version and to get it right. But the extent to which it’s become a hit is just unbelievable. I was at the Globe the other night watching Julius Caesar and in the interval I was mobbed by these Canadian schoolchildren, it was extraordinary, this great big contingent from Canada, once one of them had recognised me, and it was all ‘Sherlock, Sherlock, Sherlock’.

What projects are you working on at the moment?

I’ve just been filming Matt and Lucia for BBC1, and also Wolf Hall, which I finish next week for the BBC. That’s very exciting, Mark Rylance and Damian Lewis as Henry VIII. I’ve been doing both of those all summer and now I’m writing Sherlock!

Doctor Who: Deep Breath will air on BBC One on August 23.