The mastermind of Britain's 1963 Great Train Robbery, Bruce Reynolds, died on Thursday aged 81, his son said.
Reynolds was the brains of a gang that held up a mail train in southern England and made off with almost £2.6 million -- worth around £40 million today (47 million euros, $63 million).
"I can confirm that he has passed away and he died in his sleep," said his son Nick.
"He hadn't been well for a few days and I was looking after him."
Born in London, Reynolds was a petty criminal who was responsible for planning the robbery of the post office train which ran between Glasgow and London on August 7, 1963.
The bespectacled Reynolds went on the run after the robbery, which has been mythologised in several films and books, but was captured in 1968 and spent 11 years in jail.
After his release he wrote an autobiography.
Another member of the gang, Ronnie Biggs, famously escaped from prison after less than two years and fled to Brazil.
Reynolds travelled to Brazil in 2001 to persuade Biggs to return to Britain after 35 years on the run to serve the rest of his prison sentence. Biggs was freed on health grounds in 2009.