LONDON (AFP) - Four Dutchmen appeared in a British court on Wednesday charged with plotting to smuggle cocaine from Colombia to Scotland using a "James Bond-style" underwater vehicle.

The men plotted to take 108kg of the drug from a ship off the west coast of Scotland using a Seabob submersible jet ski and other scuba diving equipment, it is alleged.

Henri van Doesburg, 68, Arnold van Milt, 49, Roderick van Doesburg, 23, and Darryl-Jay van Doesburg, 22, are on trial at Leeds Crown Court in northern England, charged with conspiracy to import illegal drugs into Britain.

State prosecutor Paul Mitchell told the jury that customs officers found more than 50 packages of extremely high purity cocaine in the rudder space of the Cape Maria vessel on May 9.

The operation led by Britain's National Crime Agency yielded a haul with a potential street value of around £16.2 million (S$33.2 million).

Mitchell said Roderick and Darryl-Jay Van Doesburg and Van Milt all had scuba-diving experience and planned to recover the drugs from the outside of the ship.

A police search of their car and their inflatable speedboat turned up dry suits, other scuba-diving equipment and the Seabob.

"You might have seen them used by James Bond and James Bond's adversaries," Mitchell told the jury.

"It's the kind of thing you use if you need to travel underwater at high speed."

Mitchell alleged there were parallel movements between the defendants and the Cape Maria going between Britain and the Netherlands, while a document about the ship was found on one of Van Milt's phones.

"The Cape Maria importation of cocaine in May was merely an example of an ongoing conspiracy of repeated importations of large quantities of cocaine into Europe on vessels from South America."

The defendants deny the charge. The trial continues.