SHERLOCK actor Andrew Scott will star as a secret agent in the new adaptation of Swallows and Amazons.

Scott, who is the sinister Jim Moriarty in the hit detective drama, will play a spy called Lazlow in pursuit of Jim Turner (Rafe Spall), who it is believed, in the original novel, was based on Arthur Ransome, the novelist.

But the filmmakers behind the feature length film have been inspired by Ransome’s secret life as an agent for MI6 and have based Turner on Ransome, the spy.

Revelations about the writer's role as a secret agent were disclosed a decade ago when the Government released its files on Ransome’s activities in Russia between 1914 and 1937.

“He’s a very charismatic character, and there is humour and warmth in the character,” Scott told Variety magazine. “It’s a great part; it’s very witty. It’s a very attractive character to play, so I’m delighted to be on board.

“The chief reason I’m on board is because I love the storyline. That’s the thing that attracts me to any project - a great script and a really good story."

Scott has also been cast in the latest James Bond movie - Spectre - and told the magazine he is 'delighted' to be starring in his first movie made for children.

“I’m delighted that this is a film that my godchildren can come and watch, because some of the stuff I’ve done before has been a bit adult themed,” he said.

“I don’t think films made for children need be any less accomplished than those made for adults: just look at Paddington last year, which is such a beautiful film. Standards have to be very high because children have very good instincts for what is believable and relevant."

Scott joins the cast alongside Spall as Turner, Kelly Macdonald (No Country for Old Men, Boardwalk Empire) as Mrs. Walker, Gwendoline Christie (Game of Thrones) as Mrs. Blackett, Jessica Hynes (Shaun of the Dead) as Mrs. Jackson, and BAFTA award-winning English comedian, actor and writer Harry Enfield as Mr. Jackson.