SHERLOCK writer Mark Gatiss has revealed the show could be axed after admitting that top stars Benedict Cumberbatch and Martin Freeman are incredibly hard to pin down.

Fans are desperate to see whether the show will return after the last series finished on Jan 15.

2 Series four could have been Benedict Cumberbatch and Martin Freeman's last outing as the famous pair after writer Mark Gatiss hinted that scheduling issues might get in the way Credit: BBC Press Handout

Speaking at the WhatsOnStage awards last night, Mark teased: “I honestly don’t know if there will be any more. It’s incredibly difficult to get Benedict and Martin’s diaries to align.

“And obviously we left it in a very happy place…if that’s the end I’d be very happy where we left it.”

Mark also told how the last day of filming ended with a “whimper”.

“The last day tends to be an odd day—it’s never quite as you imagine it. But we did actually try and contrive it so the very last shot was Benedict and Martin running out of the building.

“Then we realised that we had to do one last shot the next day of Martin falling over—so that’s how it ended. As usual these things end with a whimper.”

2 Mark Gatiss revealed that the final day of filming was a bit "odd" and went out with a "whimper" Credit: Getty Images - WireImage

Last week it was announced loyal viewers had voted Benedict’s Sherlock as the BBC’s favourite character.

Benedict, 40, said: “Who would have thought a high functioning sociopath could be so popular with people all over the world.”

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The Sun also revealed the future of the was uncertain after sources claimed Martin and Benedict had a “frosty friendship”.

A source said: “Benedict and Martin aren’t mates and they don’t spend time together away from the show.

“They’re professional and very polite to each other but there’s not the warmth you’d expect after filming together for six years. There isn’t a huge desire to come back for another season.”