IN a scene that might have come from a James Bond thriller, a secret boatyard has been discovered in a South American swamp where drug barons were building submarines with the aim of landing tons of cocaine on to American beaches.

A pair of submarines found among Colombian mangroves 10 days ago has bolstered intelligence claims that narco-terrorists are forcing engineers to help them to acquire a means of evading coastguards and satellites.

The 50ft-long submarines were found on slipways close to a river that would have allowed them to escape through Colombia’s largest port, Buenaventura, and into the Pacific Ocean. One of the vessels was ready for its maiden voyage and the second was 70% complete. They were protected by armed guerrillas and camouflaged beneath tropical leaves.

The official account maintains that they happened to be discovered by a passing military patrol, but observers suggest the military was tipped off by US intelligence operatives in the region.

Captured workers described how they had sweated at gun-point to meet a Christmas deadline set by the Revolutionary Armed Forces of Colombia (Farc), the terrorist group that controls up to a third of the country and trades cocaine for weapons. The workers have not been charged with any crime.

The fibreglass submarines each had a conning tower and periscope, four bunk beds and room to carry five tons of cocaine which would fetch £50m in the United States. They were fitted with diesel engines, radar antennae to navigate the western coast-line and 20ft air tubes for when they were submerged.

Colombian police said the vessels were more sophisticated than 13 other submarines seized in the past two years and were substantial enough to reach Mexico or, if refuelled at sea, California – about two weeks’ sailing from Buenaventura.

“They’re learning fast,” said a drug enforcement official. “They used to work with Russians but now they import teams of Asian engineers who train local engineers whose families are held hostage until the job is done. We don’t know how many submarines are already at sea. We can only hope that many do not complete their missions.”

The submarines are the brain-child of Jorge Briceno Suarez, also known as Mono Jojoy, a veteran Farc commander wanted for killing missionaries and forcing children into the army. He justifies trading with US drug importers as “exporting suicide”.

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