British police on Wednesday confiscated a 340-million-euro stash of cocaine from a luxury yacht in Southampton, England.

Detectives said it is the biggest ever seizure of the drug the UK has ever seen. The bust was made after a joint operation with French and Dutch authorities.

The cocaine, weighing 1.2 tonnes, would be enough to satisfy around a third of Britain’s annual demand for the drug.

It was found expertly hidden beneath the bathing deck of the yacht, the UK border agency said.

The cocaine was originally packed into the specially prepared space on the vessel in Venezuela before the yacht itself was transported from the British Virgin Islands to Southampton in a cargo ship.

With a purity of 90 percent, the seized cocaine is of a much higher purity than the average seized in the UK, at 63 percent.

Along with the cocaine, 40,000 euros in cash was discovered along with a firearm. Six men have been arrested in the Netherlands and Belgium.