Britain in the 1960s was captivated by the daring of the Great Train Robbery, and the sheer scale of the money stolen. But when the accused men stood trial in April 1964, the judge was determined to send a message that such crimes would not be tolerated. Fourteen years later, several of the convicts talked to the BBC.

On 16 April 1964, Robert Welch was one of the 12 men found guilty of a notorious heist in Aylesbury Crown Court. Fourteen years later, in 1978, he was on the BBC's documentary and current affairs programme, Man Alive, and recalled seeing local dignitaries jostle for positions in the courtroom to hear the sentencing. "This was what they had all come to watch. The climax of the play, the drama," Welch said. "And the medieval setting in which we were sentenced, you know, it was a bit chilling."

Welch and his fellow convicts had fallen a long way since pulling off one of the most audacious and lucrative thefts the UK had ever seen: the Great Train Robbery.

Welch and his co-defendants were part of a band who held up a Royal Mail night train travelling from Glasgow to London. The robbers had made off with £2.6m in used banknotes, a record haul at that time, and the equivalent of over £50m ($65.8m) today. At the time of Welch's trial, police were still hunting for three of the people they suspected had been involved in the crime.

To execute this carefully orchestrated robbery, 15 members of two of London's biggest criminal gangs had worked together, each tasked with a particular role in the plot. "They were regarded as the elite of the criminal world," Reginald Abbiss, who had covered the crime for the BBC as a young reporter, told the Witness History podcast in 2023. "You had to have a certain talent and audacity, certain abilities to be able to pull a heist of this magnitude and they came together because they needed a multitude of talent."

The daring robbery took place just after 03:00 on 8 August 1963. The first step the criminals had taken was to cut the phone lines to stop an alarm being raised. They then rigged the train signals to stay red. "They put a glove over the green light, they wired a cheap battery up to the red light and this, of course, meant the driver had to slow up," said Abbiss.

Seeing the red light, the train's driver, Jack Mills, stopped the engine, and his co-driver, David Whitby, climbed out to use the trackside phone to find out what the problem was. That's when Whitby discovered that the line had been cut, and he was set upon by masked men wearing boiler suits. In the meantime, a masked robber burst into the train's cab to restrain the driver. When Mills tried to put up a fight, another gang member hit him over the head, rendering him semi-conscious.

"The one glitch, if you like, was the fact that the train driver… tried to resist," said Abbiss. "One of the robbers hit him on the head with a cosh. A lot of blood and down he went."

The gang had been given inside information that the cash and high-value packages were held in the train's front two coaches. And because it was a Bank Holiday weekend, it would be carrying more money than usual.

Although there weren't any police onboard, there were more than 70 Post Office employees, mostly in the rear carriages, where they were busy sorting letters. The criminals who had already familiarised themselves with the train's operation and layout quickly uncoupled the two money-laden carriages. The plan was to detach them and drive them away from the steep embankment to a predetermined rendezvous where it would be easier to unload the bags of cash.

It was then they hit a problem. "They had a driver to drive the train, he couldn't get the train going, and they had to pull the original driver, Jack Mills, up from the floor and threaten him and say, 'Drive the train,'"........

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