The police investigation into the Great Train Robbery was commemorated last night on the eve of the 50th anniversary of the crime.

Former Buckinghamshire Constabulary officers were praised for the work they did at the time of the robbery and during the search for the culprits.

On August 8, 1963, a gang of robbers, masterminded by Bruce Reynolds, stopped the Glasgow-Euston overnight mail train - which was carrying huge numbers of used bank notes - as it passed through the Buckinghamshire countryside close to Cheddington.

Twelve of the robbers were jailed for a total of over 300 years but more than one broke out of prison, including Ronnie Biggs, who spent over 30 years on the run before he finally returned to Britain in 2001 to face arrest.

Reynolds returned in 1968, five years after the crime, and was captured in Torquay.

He was jailed for 25 years.

Two police officers who were involved in the investigation attended the event alongside serving Thames Valley Police officers at Eynsham Hall in Witney, Oxfordshire.

Keith Milner was a detective at Aylesbury at the time of the robbery, while John Woolley was a PC and discovered Leatherslade Farm, where the men hid after committing the crime.

Last month Biggs insisted he was proud to have been part of the gang.

The famous fugitive, who celebrates his 84th birthday today, escaped from prison in 1965 and spent 36 years on the run.

Released from prison on compassionate grounds in 2009 due to ill health he is still alive, being cared for in a north London nursing home.

He has few regrets about the crime that made him a household name.

Biggs, who cannot speak and communicates through a spelling board, said: "If you want to ask me if I have any regrets about being one of the train robbers, my answer is, 'No!'. I will go further: I am proud to have been one of them."

A new book has been published to mark the 50th anniversary - The Great Train Robbery - 50th Anniversary, said to explain first-hand the complete story of the robbery.

Both Biggs and Reynolds, who died in February, contributed to the book.