Documentary claims to reveal identity of the mastermind behind the Great Train Robbery for the first time.

Signature Entertainment is to release documentary The Great Train Robbery: A Tale Of Two Thieves in UK cinemas this October, and will make the feature available on DVD and On Demand from October 6.

Directed by Chris Long, executive producer of The Mentalist, the film features Gordon Goody, one of the main instigators behind the heist who reveals the identity of the missing mastermind behind Britain’s most famous heist – the elusive “Ulsterman”.

The film is based around first person testimony from more than 20 hours of interviews.

The Ulsterman provided the 15 train robbers with vital inside knowledge that made 1963 robbery possible. They got away with more than £2.6m (the equivalent of £45m today), with the Ulsterman getting a share worth the equivalent of £5m today.

While his identity has been the subject of intense scrutiny by the public and police, it has always remained a fiercely guarded secret. The film claims to identify him for the first time.

Executive producers are Chris Long, Erin Donovan and Simon Howley and it marks a collaboration between London’s Kowalski Inc and Los Angeles’ Scallie Filmworks.