'Sherlock' will be axed if lead star Benedict Cumberbatch quits the show.
Benedict Cumberbatch as Sherlock
The BBC One mystery series based on Sir Arthur Conan Doyle's famous stories could be in trouble if the 40-year-old hunk decides to leave his role as the titular detective, as the show's mastermind, co-writer and star Mark Gatiss - who portrays Sherlock's brother Mycroft - admits they wouldn't want anyone else to take over from him.
He admitted: "We couldn't do it without him, of course not.
"We couldn't re-cast Sherlock. It's not a show we are churning out.
"It's a special thing and we couldn't do it without Benedict.
"We're very lucky to have the keys to Baker Street at the moment."
The 50-year-old television star - who was also worked on rival series 'Doctor Who' - says even if the show reaches its end, it's guaranteed to leave behind a legacy as Benedict and his sidekick Watson [Martin Freeman] are one of the "definitive" modern-day version of the detective duo.
He told the Daily Star newspaper: "Benedict and Martin [Watson] have become the definitive Holmes and Watson of our age. I don't think you will need to argue that.
"The characters are immortal and when we finish there will be more interpretations."
Though it has been speculated series four - which drew to a dramatic close on January 15 - would be the last, Mark admitted they would "love to" return again in the future and believe they ended the programme on the right note to do that.
Mark previously said: "The reason we [ended with] Rathbone Place is that, actually, if we do come back - and we would love to come back - we could absolutely very easily start with a knock at the door and Sherlock saying to John 'Do you want to come out and play?'. They have become the two heroes that we always knew them to be."
However, Benedict and Martin, 45, could hinder the chances of a new season as they reportedly have a frosty relationship off screen.
A source said recently: "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 series."
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