'Grantchester' may return for a fourth series - but with a different actor as the lead.

The third instalment of the popular detective drama came to an end two months ago and, although it received rave reviews, writer James Runcie has admitted the next batch of episodes probably won't hit television screens for a little while as James Norton - who plays Anglican vicar Sidney Chambers in the show - is "hot property" and producers may now need to look into the possibility of finding someone to replace him.

Speaking to the Daily Mirror newspaper, he said: "James Norton is in such big demand now that I've no idea if he'll be available to film a new series.

"But 'Death in Paradise' has replaced the leading man, and that's still going strong, so if the worst comes to the worst..."

And it's not just the writer who can see the show excelling without the 32-year-old actor as Robson Green - who plays Detective Inspector Geordie Keating in the programme - is confident the viewers will still tune in if it's given a huge cast shake up one day.

He said previously: "The series can carry on most definitely. Whether I'm in it or James is in it, or whoever, is another question. It is a secure entity now and it's up there with the best of what ITV's got to offer at the moment."

'Death in Paradise' first hit television screens in 2011 with Ben Miller as the lead and, although it was a huge success, he decided to quit the role two years later.

But, rather than pull the plug on the show altogether, bosses decided to replace him with Kris Marshall, who played Humphrey Goodman, for three series until 2013.

Kris announced earlier this year that he was turning his back on the show in order to spend more time with his family and it was confirmed a few weeks later that Ardal O'Hanlon will take over the reins as the lead character in series seven.