Sherlock co-creator Steven Moffat has revealed that he has already plotted out future series' four and five of the detective show.

Speaking at a screening of the series three finale, entitled His Last Vow, Moffat assured fans that they have some great storylines in the works.

"Rather excitingly, Mark [Gatiss] 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.

He continued, "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."