The Royal Navy has carried out its biggest drug bust in Britain's history after seizing three tons of cocaine from a tugboat. 

Together with the U.K. Border Force and the National Crime Agency (NCA), the Royal Navy intercepted a Tazmanian tugboat named MV Hamal 100 miles off the Aberdeenshire coast at the North Sea last week. About nine Turkish nationals, between the ages of 26 and 63 were arrested in connection to the drug bust. They remain in custody with the authorities and have been charged with drug trafficking offences.

The boat was setting sail for the Canary Islands, while the drugs were believed to have originated from South Africa, according to reports from the Daily Mail. Because of its unusual route, the French marine grew suspicious and alerted the NCA. After the boat was stopped by the Royal Navy, officers of the Border Force rummaged through the vessel and found the haul.

"The search of this vessel has been lengthy and painstaking. The result is this massive discovery - believed to be the biggest single class A drug seizure on record in the UK," said NCA senior investigating officer John McGowan.

"Our investigation continues, but the operation was only possible thanks to the close co-operation between the NCA, Border Force, the Royal Navy, plus the French DNRED and our other international partners."

The Turkish drug traffickers are set for another day in court on Tuesday, May 5.

The drug bust is believed to be worth £500 million, five times more valuable than a previously biggest drug bust in the U.K, which took place in Scotland in 1991, according to Metro. At that time, authorities were able to confiscate £100 million worth of cocaine and sentenced its perpetrators to 17 years.

About 25 to 30 tons of cocaine are reportedly being smuggled into U.K. yearly, making the region a profitable market for drugs. Shipments are brought into Europe through cargo vessels, container ships, yachts or air couriers, with crime groups running the drug trade as far as the Netherlands and Spain.