The robbers played Monopoly with real money after the huge heist

Thames Valley Police are marking the date on Friday with a new and expanded exhibition at the Force Training Centre in Sulhamstead, Berkshire.

Much of the items on show were left by Ronnie Biggs and his 14 fellow robbers when they fled their hideout, Leatherslade Farm, near the Oxfordshire-Buckinghamshire border.

They include a Monopoly board the gang played with using real cash, a large number of fingerprints, and debris from the cash hoard.

Two officers from Buckinghamshire Constabulary, later absorbed into Thames Valley Police, found the items at the farm five days after the robbery acting on a tip-off.

Dubbed the "crime of the century", the Great Train Robbers held up the night mail train from Glasgow to Euston as it passed through the Buckinghamshire countryside.

The gang made off with more than �2.5m in used bank notes - worth �40m today - but a series of blunders led to their capture.

Museum curator Ken Wells said: "Our Great Train Robbery display has always been one of the most popular within the museum.

"The Great Train Robbery itself has been the subject of enduring fascination for the British public and internationally.

"This is why we have chosen to mark the events of 40 years ago with an improved display, showing more photographs, more evidence exhibits and, of course, the Monopoly board."

The museum itself is open to the public by appointment.