In the 1980s, London was rocked by a wave of violent armed robberies. One of the most daring was the raid on the Brink’s Mat security warehouse in Hounslow. It was also the most lucrative by far, netting the thieves a cool £26 million in gold bullion, and leaving in its trail a wake of violence and death. An elite unit was tasked with bringing the gang to justice, Scotland Yard’s Flying Squad. From the outset, Flying Squad officers suspected the robbers had inside help. But which of the guards was responsible, and how to prove it?

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