On the 26 November 1983, six armed men broke into the Brink’s-Mat security depot near London’s Heathrow Airport, and inadvertently stumbled across gold bullion worth £26m. What started as 'a typical Old Kent Road armed robbery' according to detectives at the time, became a seminal event in British criminal history, remarkable not only for the scale of the theft, at the time the biggest in world history, but for its wider legacy.