A writer of breathtaking true stories, with a gift for unearthing seldom-told tales of wartime courage, could soon be seeing another of his books played out on the big screen – little more than a year after Hollywood first came calling.

Dr Mark Felton, who grew up in Colchester, was busy researching another war story when he discovered an “absolute gem” about the attempts of 13 senior British and Commonwealth officers to flee an ‘escape-proof’ prisoner-of-war camp converted from a medieval Tuscan castle on Mussolini’s personal orders.

“They were taken prisoner in the desert by Rommel,” said Dr Felton, whose 16th book, Zero Night, was picked up by the makers of period drama Saving Mr Banks last year.

“They were handed to Mussolini and taken to a castle above Florence. The youngest was 48 – the oldest 63. They were determined to escape.

“Many were grizzled First World War veterans, but the Italians didn’t expect them to try this stuff on. They made crazy escape attempts, and spent six months digging a 60ft tunnel through a solid wall, eventually fleeing to Switzerland.

“I found out that their families were very keen for the story to be told.”

Hollywood’s adaptation of Zero Night is already well into pre-production, according to Dr Felton, who has been recruited as a consultant on the movie.

“I think the screenwriters have done a fantastic job,” he said. “The option has been renewed for another year, so they’re obviously serious about developing it.”

Dr Felton secured a deal for Castle of the Eagles: Escape from Mussolini’s Colditz to be made by Entertainment One – the company responsible for distributing such recent hits as Spotlight.

“I’ve met some of the producers and feel it’s in safe hands,” said the 42-year-old father-of-one, who now lives in Norwich.

“I thought having one book noticed by Hollywood was extraordinary, but I’m bowled over to have two in that machine.”