General secretary of the train driver's union Aslef said although they feel sorry for Ronnie Biggs' family, "We have always regarded Biggs as a nonentity, and a criminal, who took part in a violent robbery which resulted in the death of a train driver".
Mick Whelan said, "Jack Mills, who was 57 at the time of the robbery, never properly recovered from the injuries he suffered after being savagely coshed by the gang of which Biggs was a member that night."
Mr Mills died a few years after the Great Train Robbery took place.
The Great Train Robber Ronnie Biggs has died at the age of 84.
Biggs was part of a group who stole £2.6million from a train (equivalent to around £40 million today) in Ledburn, Buckinghamshire in 1963.