Danny Pembroke, a former soldier, fled to the US in the wake of the heist, but moved back to Kent where he died in 2015, aged 79.

The robbery is one of Britain's most notorious crimes.

A 15-strong gang of thieves attacked a Royal Mail train on its way from Glasgow to London.

In his lifetime, he never admitted to playing a part in the robbery, although he was a suspect.

Some of the gang who were convicted were sentenced to 30 years behind bars.

Pembroke didn't speak about the robbery but his son Danny admits his involvement in a new Channel 4 documentary.

Danny outlines how his dad was questioned by cops but released without charge due to a lack of evidence.

Pembroke spent two years in Florida, thanks to the help of his underworld contacts.

Pembroke managed to live a comfortable life after he moved back to England because of his £150k share.

His son said: "We had a comfortable life but not over-extravagant. It was nice, it was above mediocrity.'"

The Great Train Robbers are estimated to have stolen more than £2.6million - around £46million today.

Most of the money was never recovered.

Their loot is believed to have been split into £150,000 shares, with smaller amounts for associates who played a lesser role in the heist.

The Great Train Robbery: the Hidden Tapes, will be broadcast on Channel 4 at 9pm on August 12.