Officers boarded the World War II torpedo boat at high speed

A huge cocaine haul - believed to amount to 3.6 tonnes and valued at more than �250m (350m euros) - has been seized in a mid-Atlantic high speed swoop.

Eight men were arrested after Spanish customs officers boarded a former World War II motor torpedo boat at high speed.

The boat was allegedly being used to transport the drugs and was thought to be heading for Spain or Portugal.

The British-led operation involved the Royal Navy warship HMS Cumberland, Royal Fleet Auxiliary Wave Knight and aircraft of the Fleet Air Arm.

The commanding officer of Cumberland, Captain Mike Manser, said the operation had been a "great success".

"Both ships - and we had two naval helicopters with us - managed to converge on the vessel and, to its great surprise, we were suddenly there in the middle of the Atlantic so they stopped very quickly," he said.

Significant haul

"This enabled us to put Spanish customs officers on board the boat. They were certainly quite surprised and there was no resistance."

The eight people arrested are being questioned in custody in Spain.

The captain is from the Dominican Republic and the other seven from Greece, while the boat was registered in Honduras.

Customs and Excise said it was estimated a fifth of the cocaine - thought to be from Colombia - was destined for Britain.

Officials believe a fifth of the drugs were headed for Britain

The motor boat was originally a military craft built by the Germans during World War II.

Capt Manser said the Cumberland was escorting the alleged smugglers' vessel to Spain where the cocaine would be weighed.

"We don't know exactly the amount but it is certainly in tonnes rather than kilograms - figures of over 3 tonnes have been mentioned.

"Clearly it hasn't all been weighed yet but it is a very, very large amount. It is a very significant haul."

The customs minister and economic secretary to the Treasury, John Healey, said: "This operation has stopped Class A drugs reaching the streets of the UK and harming our communities."

New flexible enforcement methods and an international effort meant customs were "more than a match" for today's sophisticated drug smugglers, he said.

Chief investigation officer for HM Customs and Excise, Paul Evans, said: "This is an excellent example of our close and continuing co-operation with the Spanish authorities to tackle Class A drugs."