Sherlock stars Benedict Cumberbatch and Martin Freeman were the first to know there would be a fourth series of the BBC1 detective drama, says co-creator Steven Moffat – even before himself or the BBC's commissioners...
"We had to inform the BBC that Martin and Benedict had commissioned a new series," said Moffat.
"They signed themselves up. They both announced that they were carrying on – so that’s good.
"Benedict, at some red carpet event somewhere, said he was carrying on forever. Martin, at another one, said, ‘Yep, series four is happening’."
But if the two stars were operating slightly outside their remit as actors, Moffat is relatively confident that the BBC will go along with them just this once...
"The BBC can do what they like," he said. "They're massively powerful, don't provoke them! But I assume that unless we've really screwed up Sherlock [series three] – which we haven't – it's a big success and it will carry on, so long as Benedict and Martin want to do it."
Fans are still awaiting Sherlock series three almost two years after the season-two cliffhanger finale was first screened, with an official air date yet to be announced. And while Moffat admitted he himself did not know for sure when it would be broadcast, he did say "I would place good money on it being at the very end or the very beginning of the year."
Steven Moffat was speaking at a Radio Times-sponsored event at the Cheltenham Literature Festival