Although not officially announced by the BBC, at last night’s screening of Sherlock’s series 3 finale, His Last Vow, writer Steven Moffat revealed that he and Mark Gatiss already have plans in place for at least two more series.

Moffat said: “Rather excitingly, Mark and I, for no particular reason, we just got out of the rain and sat at the top of the [Sherlock] production bus… and we just started plotting out what we could do in the future. And we plotted out the whole of series four and five.”

“So we have got plans – but our plans don’t tend to be ‘Let’s blow up the world or cast the most famous person in the world’ they tend to be ‘What exciting twists and turns can we add to this?’ And I think we’ve got some crackers! The ideas we had that day, I thought were the best we’ve ever had.”

On how long fans might have to wait for more adventures: “Benedict and Martin are apparently in movies! So we’ve got to schedule around them, but we’ll get them made as quickly as we can.”

However, Moffat believes that the long gaps actually benefit the show: “Sherlock started very well, the second series did better than the first and now the third is doing better than the second. It shows the benefits of starvation – put things on less often!”