UK authorities have seized over 2 tonnes of cocaine in a raid on a luxury yacht off the coast of southern England, the National Crime Agency said Saturday.

British authorities said they arrested six people on Thursday evening after discovering the drugs with an estimated street value of £160 million ($221 million) on a Jamaican-flagged yacht sailing from the Caribbean. 

One British man was arrested on suspicion of drug trafficking along with five Nicaraguans.

The NCA released photographs of the drugs stored in black waterproof bags in the lounge of the docked Kahu yacht.

"There's no doubt these drugs would have been sold on into communities across the UK," said NCA deputy director Matt Horne.

The seizure "will smash a hole in the OCG's (organised criminal gang's) plans and ability to operate," he said.

The NCA said it intercepted the yacht when it was 80 miles (130 kilemetres) off the coast of the port of Plymouth after receiving evidence gleaned from a sting operation by the Australian Federal Police, who participated in the raid.

This summer the Australian police and the FBI revealed they had carried out a sensational operation persuading criminal networks to use supposedly encrypted phones called ANOM that were in fact copying messages to the law enforcement authorities.