In 1983, armed robbers stole a large amount of gold from the Brink’s-Mat warehouse near London’s Heathrow airport. Police were in a race against time before the gold was melted, disguised and sold back on the open market, fuelling criminal enterprise on an unprecedented scale.

Billed as “the crime of the century”, the ensuing investigation lasted until 1992 and became one of the country’s longest police investigations. BBC One’s serial dramatisation of the crime aired its concluding episode on Sunday (March 19), and the broadcaster is set to air a documentary that hears from the detectives who worked on the case.

Airing on BBC One on Monday, The Gold: The Inside Story will see Detective Chief Superintendent Brian Boyce, who led the investigation, and DC Tony Yeoman speaking on film for the first time since the robbery almost 40 years ago. They will disclose the challenges they faced and the strategy they used in the hunt for the gold.

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Speaking in the documentary, DCS Boyce says: “Our task was far greater than just arresting the robbers, we hadn’t even recovered the dust of the gold. We had to work extremely hard, follow the trail and recover as much of the gold as possible.”

Using archive footage and eyewitness testimony, the documentary will detail the cat-and-mouse chase across borders and continents and the tracking of a corrupt network who helped to launder the money. But what happened in the Brink’s-Mat robbery?

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What happened in the Brink’s-Mat gold robbery?

At 6.40am on November 26, 1983, six armed robbers posing as security guards confronted staff at the Brink’s-Mat security depot near Heathrow airport. The robbers disabled the building’s security system, doused staff in petrol and threatened them with a lit match to force them into revealing the combinations to the warehouse vault.

The thieves were expecting to find cash, but once inside they found three tonnes of pure gold, comprised of 6,840 bars in 76 cardboard boxes. The gold had been stored at the warehouse overnight and was due to be transferred to Hong Kong the following day.

The thieves also stole 1,000 carats of diamonds and $250,000 of traveller’s cheques. Their haul had a total value of £26m, an equivalent in today’s money of nearly £100m.

Not knowing what to do with the gold, they recruited several criminals to assist in melting it and selling it to unsuspecting buyers. Police say that half of the gold was melted and sold back to legitimate dealers, with much of it becoming expensive jewellery.

According to the BBC, it is claimed that anyone wearing gold jewellery bought in the UK after 1983 is likely wearing Brink’s-Mat. More than £10m worth of the stolen gold was buried and has never been found, while some vanished into a criminal underworld and reappeared in foreign bank accounts across the world.

Just two of the armed robbers have been caught and convicted for the heist, while at least 14 people have been convicted of helping to launder its proceeds. The thieves succeeded in their robbery with the help of an inside man, Anthony Black, who was working at Brink’s-Mat as a security guard.

He was the brother-in-law of notorious London criminal Brian Robinson, and when brought in for questioning, Black confessed and gave up key information about Robinson and other members of the gang. Black’s testimony led to the convictions of Robinson and Mickey McAvoy.

Both men were jailed for 25 years for their parts in the raid, while Black received six years.

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