You can't prove I stole it. The world's biggest peacetime robbery ever. Exactly what happened when 6 thieves accidentally stumbled upon 6,840 gold bars in 1983. They're calling it the largest heist in history. Six armed robbers broke into a Brinks high security warehouse at London's Heathrow Airport just before dawn this morning. Police say the job took just 27 minutes. Robert, what are you seeing from above? It seems three tonnes of pure gold bullion were loaded into two stolen Ford Transit vans.

One white, one blue. I'm hearing the gold wasn't the original target. That the thieves didn't know it was in the warehouse. I've been hearing the same thing. They didn't know the gold was there. They were only expecting to find a couple million in cash. But upon seeing the gold, they loaded it up. Drove on Bath Road to the M4 motorway, splitting the convoy into two. One van went to Kent. The other van went to South London.

Within a month, two thirds of it had been moved to Bristol. The rest stayed in the original safe house in Kent. In the garages where they stored it, they melted it all down using propane fueled furnaces, with many of the furnace parts being common items that you'd be able to find on a construction site. But to make it fully untraceable, they mixed the melted gold with copper so bars could be passed off as scrap jewelry remnants.

Over the next two years, the new gold bars smelted in Bristol were sold back into England in black market deals using London pubs and through an employee at the Sheffield Assay Office, one of just four official England organizations who test gold for purity. The ones in Kent were packed into car doors and moved through France and into Switzerland. This tale ends for us here, though we could go on because this became a ten year saga that included more than ten murders.

Members of the gang getting caught and turning on each other, casinos, smuggling. It is a fascinating story, but to this day only a third of the gold has been recovered. Johnson Matthey Bankers, the official gold refiner of the Bank of England, which is Britain's central bank. They were the victims. It turned out to not be the government's gold they were moving this time. But what if it had been?