'Sherlock' creator and showrunner Mark Gatiss didn’t spare the dramatics when talking about Benedict Cumberbatch’s importance to the show. When underlining the integral role his leading man plays, the words “under” and “bus” were uttered.

Benedict Cumberbatch and Martin FreemanBenedict Cumberbatch and Martin Freeman are indespensible to Sherlock, says Gatiss

"If Benedict went under a bus tomorrow it would be the end of the show,” Gatiss announced to the Daily Mirror. "Benedict and Martin are our stars. We do three episodes a year and although people want more that's all we can do. They are so famous now it's difficult to get them."

The great success of the show has bred problems for Gatiss, who faces a tough job keeping his stars together, not to mention synching their calenders in the wake of major Hollywood roles for both Cumberbatch and Freeman, who both starred in 'The Hobbit: The Desolation of Smaug', and are reprising those parts as Bilbo Baggins and Smaug respectively in the third and final movie, 'There and Back Again'.

This has meant Sherlock fans won’t see their mercurial detective and his grounding partner until 2016, which hasn’t been a popular decision at all. "Everyone wants to carry on doing Sherlock. It's a simple matter of schedules - particularly Benedict and Martin,” explained Gatiss.

"They've become superstars, which is brilliant, but we all want to carry on as long as we can. There was suddenly a kind of outraged response that it might not be back until 2016 but that's precisely how long it always is. It's always two years! But we'd like to return soon, of course."

The third season of Sherlock – which lasted for three feature length episodes – explored the chemistry between Sherlock and Watson even further, which the middle episode – The Wedding Speech – attracting plenty of attention for its original pacing and character development between the show’s stars.