'Sherlock' may not be on screens for much longer.
The drama series' co-writer Steven Moffat recently confirmed that he and Mark Gatiss will be back to pen a fifth instalment of the popular show but the 50-year-old screenwriter has admitted the pair of them are constantly toying with the idea of bringing it to an end because it's so hard to get the schedules of Martin Freeman (Dr. John Watson) and Benedict Cumberbatch (Sherlock Holmes) to line up every year.
Speaking to UKTV podcast 'A Stab in the Dark', Gatiss said: "It's not lack of will - it's a nightmare to schedule. It was very, very hard to schedule the last series, because of Martin and Benedict's availability. And Steve's and mine.
"There is always that 'Fawlty Towers' principle of, 'Let's just leave it'. We've had the keys to Baker Street for a while, but one of the wonderful things is that they're always shared. They were shared while we were making it. There's nothing wrong with saying, 'That was our version, somebody out there go and do their version'."
However, it seems Gatiss and Moffat have different views as the 55-year-old television writer - who is currently executive producer for 'Doctor Who' - is adamant that there will be another instalment of 'Sherlock' - but it won't be anytime soon.
He said: "We did [the last series] a year ago, just about, and I've been flat-out on 'Doctor Who' ever since. So I haven't really thought about it. Mark [has] been doing other stuff as well, so we haven't sat down and had a proper talk about what we would do with another series. I assume we will. I sort of assume we'll come back."
Although Moffat said shortly after series four concluded in January that it would be "fine" if 'Sherlock' didn't return for anymore episodes.
He said at the time: "It's not like we haven't had our reward for doing that show. It's been such a phenomenon. Not doing it again would be fine. If that was it, then that would be it. None of us will starve in the street - well, I might."