Detectives investigating the £26 million Brinks-Mat bullion robbery are digging for hidden gold in Sussex.
Scotland Yard said officers from the Flying Squad were searching an area in Old London Road, Ore, near Hastings.
About 30 officers were today searching two yards behind a builders' merchant looking for "proceeds believed to be connected with the Brinks-Mat robbery", Scotland Yard said.
Detective Superintendent Jon Shatford, head of the Flying Squad, is leading the search operation.
Officers were looking through timber in one yard with a mechanical digger standing by.
A Scotland Yard spokeswoman said: "We have found nothing yet and it may take some time to look through the area.
"We believe this may be connected to the Brink's-Mat robbery. We are looking for proceeds from that incident. There was some gold bullion taken but we have found no gold so far.
"It depends how long it takes to find anything before we can say how long this operation will last."
The robbery of gold bullion and jewels worth £26 million from the Brinks-Mat vaults at London's Heathrow Airport on November 26, 1983, was Britain's biggest.
A bribed security guard let six armed men into a warehouse and within an hour had they pulled off "the heist of the century".
The gang doused security guards at the warehouse in petrol and threatened them with a lit match for the combination numbers of the vault.
It is thought more than £17 million of the cash realised from the gold has been accounted for by police, with the rest allegedly invested in property in Britain and Spain or drugs.
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.
Only two of the robbers have been convicted. Michael McAvoy and Brian Robinson are each serving 25 years.
Others have been convicted of handling the bullion or making profit from the robbery. They include convicted killer Kenneth Noye.
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