At 3 a.m. on Tuesday, 8 August 1963 the UK Post Office 'Up Special' train stops at a red signal. The train's fireman climbs out of the train and walks over to the emergency call box, as regulation says he should, to find out whether there is anything blocking the tracks. He notices a man dressed as a line worker walking towards him. The line worker and two other men in balaclavas attack him, push him down an embankment and handcuff him.
The man dressed as a line worker was Ronald "Buster" Edwards, a retired boxer and club owner. He was part of a 15-strong gang that robbed the Up Special; a 17-carriage traveling ,ail-sorting office carrying letters, 75 postal workers, cash, and other valuables from banks and other financial institutions in Scotland to London. One of the gang members boards the locomotive and beats the engineer, Jack Mills, with an iron bar. Mills receives head injuries that he never fully recovers from. Despite these injuries, Mills is forced to undo a brake on the train, allowing it to move after some carriages are detached. The gang disconnects all but the first two carriages of the train and the train begins to move again.
The carriage that the robbers are after is two back from the locomotive. The High Value Packages Coach. In this carriage was over £2,600,000 (£40,000,000 in today's money) in untraceable £1, £5, and £10 notes. The HVP coach contains more than usual because the train was leaving after a bank holiday weekend. Gang members break their way into this coach and restrain the startled workers, who were alarmed by the sound of the rest of the train being disconnected.
At 3 30 a.m. the train is stopped in Leighton Buzzard in Bedfordshire, where the gang forms a human chain to unload 120 mail bags into nearby trucks, which they used to make a swift getaway. During this unloading, the postal workers were bound, gagged, and left facing the ground. The gang makes a getaway to Leatherslade Farm, purchased by gang member and mastermind Bruce Reynolds a few weeks earlier. They had originally planned to lay low for a few weeks, but after hearing that the police were already after them, they decided to take their individual cut of the money and leave. They had hired a man to clear the farmhouse of potential evidence, but he simply took the money and ran, leaving large amounts of evidence for police to find later, which lead to many of the arrests that followed.
Detective Chief Superintendent Tommy Butler and Jack Slipper, both legends of Scotland Yard were assigned to this case.
