The gold, which weighed 104 kilograms (229 pounds), was on its way to Switzerland from the Cayman Islands when it was seized on June 1. No arrests were made, police said.
The UK’s National Crime Agency (NCA) — a governmental law enforcement organization — reported that the gold was believed to have originated in Venezuela, from where it was transported to the Cayman Islands on a private jet.
Border Force agents at Heathrow Airport subsequently moved in to detain the shipment when it arrived in the UK, based on intelligence provided by the NCA.
“We believe that this shipment was linked to drugs cartels operating out of South America,” Steve McIntyre, NCA Heathrow branch commander, said in a statement. “Working with partners overseas and in the UK, we were able to quickly identify it and stop its onward movement.
“The business model of many organized crime groups relies upon the ability to move money across borders, to fund further investment in criminal activity.
“If we can stop that it not only causes disruption to the criminal network involved and prevents them benefiting from crime, it also stops that re-investment.”
Nick Jariwalla, Border Force Heathrow director, added that removing large amounts of money or gold from the control of criminal networks “hits them where they feel it most, in the pocket.”
“This was a substantial seizure and demonstrates how effectively Border Force works with law enforcement partners, both at home and abroad, to combat organized crime,” he said.
Lynne Owens, the director general of the NCA, praised the work of both teams and said that it represents “further progress” in the fight to stop the UK being used as a “route for illicit finance.”
“Excellent work by our international network and others supported by Border Force,” she wrote on Twitter.
While the gold was seized last month, a recent hearing at Uxbridge Magistrates’ Court in London allowed it to be officially held under the Proceeds of Crime Act.
The gold will now form part of an international money laundering investigation led by the Cayman authorities, with the support of the NCA.
The NCA and Heathrow’s Border Force have previously uncovered large hauls in connection to international drug trafficking from South America.
In 2017, a Heathrow security worker was charged with attempting to import cocaine worth up to £480,000 ($600,120) into the UK from South America.
The worker was on sick leave when he traveled to the airport in his uniform and met a drug courier from Colombia in airport toilets, where he was subsequently arrested by police, the NCA said.
He was later sentenced to 13 years in prison.