The £26 million stolen during the Brink's Mat robbery in 1983 may have been channelled into an offshore company set up by Mossack Fonseca, the leaked documents reveal.

The theft, dubbed the 'Crime of the Century', involved criminals stealing gold bullion, diamonds and cash from the Heathrow International Trading Estate in London.

The leaked files show that 16 months later, Mossack Fonseca set up a Panama shell company called Feberion Inc.

Revealed: Cash from the notorious Brink's Mat heist at Heathrow in 1983 may have been moved offshore by the Panamanian Law Firm. Pictured, a police officer standing outside the warehouse targeted in the heist

Documents show that the man behind Feberion Inc. was Gordon Parry, who laundered money for the Brink's-Mat plotters.

An internal memo written in 1986 by Jürgen Mossack, one the co-founders of Mossack Fonseca, showed that the firm knew it was 'apparently involved in the management of money from the famous theft from Brink's-Mat in London'.

The memo stated: 'The company itself has not been used illegally, but it could be that the company invested money through bank accounts and properties that was illegitimately sourced'.

Documents appear to show that Mossack Fonseca later took steps to prevent British police from gaining control of the company in an attempt to get the money back.

The robbery of gold bullion and jewels worth £26 million from the Brink's-Mat vaults at London's Heathrow Airport at 6.30am on November 26, 1983, remains Britain's biggest.

A bribed security guard let six armed men into the warehouse and within an hour had they pulled off 'the heist of the century'.

It is thought more than £17 million of the cash realised from the gold has been accounted for by police, with the rest believed to be invested in property in Britain and Spain or drugs.

Sentenced: Robbers Brian Robinson, left, and Michael McAvoy, right, were jailed for 25 years for the raid

Hunt for the cash: Police have for years searched for the money, pictured here in 2001, 18 years after the heist, digging up land in east London

Eleven bars of the gold were found in 1985 and melted down and a further £1 million of gold was later recovered from the Bank of England where it was being stored after re-entering the legal market.

The rest is believed to have been melted down shortly after the robbery. But police have continued to trace cash and assets linked to profits from the haul.

And Lloyd's of London, the insurance market that paid out for the stolen millions, is believed to have forced 25 people linked to the robbery to secretly pay back every penny stolen in March 1995 following investigations by private detectives.

Only two of the actual robbers have been convicted. Michael McAvoy and Brian Robinson were both both given 25 years. Others have been convicted of handling the bullion or making profit from the robbery. They include convicted killer Kenneth Noye, jailed in 1986 for handling the bullion for 14 years, reduced to 13 on appeal.

The Brink's Mat heist: How robbers pulled off the 'crime of the century'

Convicted killer: Crime boss Kenneth Noye, pictured, handled gold stolen in the heist

Shortly after 6.40am on November 26, 1983, six armed men in balaclavas – including one wearing a Trilby – entered a warehouse at Heathrow airport.

The property belonged to security company Brink's Mat and the robbers were there because they knew there was £3million in cash in the vault. They knew because their inside man, security guard Anthony Black, had told them. He even opened the door of the warehouse to let them in.

Led by Black’s brother-in-law, Brian Robinson, and Trilby-clad Michael 'Micky' McAvoy, the gang tied up the guards and poured petrol over them, threatening to light it if they didn’t comply.

Thanks to Black, they were able to identify the two most senior guards who, between them, held the keys and combination numbers for the vault where three safes were located.

Inside was more than three tonnes of gold bullion. Packed into more than 70 cardboard boxes were almost 7,000 gold bars. Someone had to fetch the van.

Weighed down by a heap of gold, the van idled its way out of Heathrow after one of the robbers wished the security guards a merry Christmas.

It didn’t take the police long to connect Black to the raid and he soon implicated Robinson and McAvoy (who punched Black when he went to identify him in a police line-up).

The pair hadn’t exactly laid low after the robbery, spending cash on property in Kent. It was rumoured McAvoy had bought two rottweilers to protect his new home and named them Brinks and Mat.

The two were later sentenced to 25 years in prison. Black was sentenced to six years. Stealing the gold had been relatively easy. The bigger challenge was selling it.

The robbers turned to crime boss Kenneth Noye, who, along with another criminal, Brian Reader, handled the gold. It was regularly taken to a smelting company near Bristol where it was mixed with copper and brass to look like scrap gold.

Manhunt: Detectives looking for clues on the Heathrow industrial estate, where the robbers struck in 1983

Sentenced: A security van with Michael McAvoy and Brian Robinson leaves the Old Baily during the trial

About £13millon-worth was disposed of in this way. The movement of cash through a local bank soon aroused the suspicion of the Bank of England and surveillance operations of known villains began.

Noye appeared in court in 1986 after police found 11 gold bars worth £100,000 on his premises. He was found guilty of handling the Brink’s Mat gold and was sentenced to 14 years in prison.

He is currently serving time in prison for the 1996 roadrage killing of 21-year-old Stephen Cameron on the M25 in Kent.

Only two of the gang that entered the warehouse were ever convicted of the crime but there were greater repercussions.

It is estimated that more than 20 people with some kind of connection to the robbery have been killed, as Britain’s criminal underworld turned on itself.