Steven Moffat has explained why fans only get three episodes of Sherlock per series and just why the wait is so long in-between each of them.

“I think Sherlock has evolved into what it is. I think what we do with Sherlock, quite purposely is that we put the 13 weeks or the 26 weeks of development into three 90-minute [films], and that gives it its feel. It gives it its pace and intensity,” he told the Huffington Post.

“If we now went to a Doctor Who-style series [of 13 episodes], which we could have done, those episodes would be a bit pale compared to the ones we do now. We say we’re making films, and if you think of it as making films, we’re making quite a lot in a short period of time. Guy Ritchie’s only made two Sherlock Holmes films – we’ve made six.

“I don’t think we could go the other route now. It didn’t go that route because of my commitment to Doctor Who; it was Ben Stephenson of the BBC, the head of drama. He suggested Sherlock should be an event-status television program. The fact is, we couldn’t keep up this level of event status if we were on every week. It’s because when Sherlock arrives back like a rock star into the amphitheater — it can’t do that every week. It can do that three times every 18 months.”

Moffat also gave an update on the status of Series 3: “Where I am is knee-deep in Doctor Who at the moment. We’ve got a notion of when we want to do [Sherlock] and we’re negotiating with everybody. We’re negotiating among Star Trek and The Hobbit and Doctor Who, which is an upscale problem to have.

“It’ll be difficult, but one of the things we do in this show is we make you wait. And then we turn up and we do a quick raid – you get three really good ones, and then we disappear again and make you wait again. That’s worked for us, and that will always be the case. It will probably extend the life of the show, because everybody gets to do other things. It’s not like “Doctor Who,” which is 24-hour-a-day slavery as long as you’re involved in it. That’s why people have to escape.”