A drowning British man was rescued by lifeguards - and then immediately arrested by police - after his overturned dingy was found to have shed one tonne of cocaine worth £48 million off the Irish coast.

The suspect, said to be in his 20s, was plunged into the freezing water after the boat in which he was travelling turned over in choppy seas and shed the load, which is Ireland's biggest ever drugs haul.

Lifeguards were called when a second man, who was also travelling in the dingy, managed to swim ashore just off the coast of Mizen Head, in County Cork, and alert them that his fellow crewman was stuck at sea.

Upon reaching the scene, rescue crews discovered the man surrounded by 40 sealed packages of cocaine about a mile offshore. Police were immediately called and arrested both men.

The drugs were wrapped in white waterproof bales said to be 3ft long by 2ft wide. Police are investigating a theory that the drugs originated in the Caribbean and a vehicle was waiting on the shore to pick up the consignment.

The arrests are the latest indication that the west Cork coastline is being used as a drug-trafficking route.

In 1996, a yacht named the Sea Mist was discovered off the coast carrying 599kg of cocaine with a street value of £28m.

Jim O'Keefe, justice spokesman for Fine Gael, Ireland's Opposition party, said the seizure shows the coastline is an open door for dealers.

“This dramatic find supports claims that Ireland is increasingly being used as a transit point in the international drugs trade,” he said.

“There have long been claims that drugs are being stored around Ireland, using elaborate installations off the coast.

“The sheer size of this haul also demonstrates the scale of the drugs problem which Ireland is now facing.”

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