Two Dutch men who provided a specialist drug retrieval service for organised crime groups have been jailed after they were caught at the Seamill Hydro.

Henri van Doesburg, aged 68, masterminded a plan to use a high-speed underwater scooter to recover 108 kilos of cocaine hidden in the rudder area of the Colombian cargo ship Cape Maria anchored near to Hunterston.

His plan was stopped by a multi-agency operation earlier this year.

National Crime Agency investigators arrested Van Doesburg’s son Roderick, his grandson Darryl-Jay, aged 22, and Arnold van Milt, aged 49, at the hotel in Seamill on the evening of May 9.

Investigators seized the underwater scooter, a rigid hulled inflatable boat with a powerful engine, wetsuits and diving equipment.

A specialist Border Force deep rummage team and divers from Police Scotland’s Marine Policing Unit had recovered the cocaine earlier in the day following an extensive search of the ship. They also found pieces of cut rope in the rudder area indicating the hide had been used before.

Van Doesburg, who was in constant contact with Van Milt using an encrypted BlackBerry, was tracking the ship on his home computer. He was apprehended by the Rotterdam Hit and Run Cargo Team the following day, and was later extradited to the UK to face trial.

Dutch officers had observed meetings between Van Doesburg and two English men at a café in Amsterdam on May 8. They heard references to “diving” and “got 120”. They recovered sheets of notepaper showing calculations and telephone numbers.

Van Doesburg and Van Milt were found guilty of conspiracy to import cocaine following a four-week trial at Leeds Crown Court. They were sentenced to 20 and 16 years respectively. The jury found Van Doesburg’s son Roderick and grandson Darryl-Jay not guilty.

David Norris, NCA Branch Commander, said: “The underwater scooter was like something out of a Bond movie. These criminals were going to use it to dive beneath the ship under the cover of darkness and recover the cocaine worth tens of millions of pounds.

“Van Doesburg and Van Milt provide a specialist drug retrieval service for organised crime groups, and we have linked them to other ships that have been intercepted carrying cocaine.

“Van Milt posed as a tourist while in Scotland and bought camping equipment as part of the cover story.

“By preventing them providing more of their services, the NCA and its partners have disrupted criminal activity beyond this one operation. There will be some very frustrated criminals out there today.” Sir Charles Montgomery, Director General of Border Force, said: “This was an excellent seizure that stopped millions of pounds worth of harmful drugs making their way onto the streets of this country.

“I would like to pay tribute to all the Border Force officers that were involved but in particular to our specialist officers from the National Deep Rummage Team.

“This joint operation is an example of the coordinated action being taken to protect our border and target the organised groups behind drug and people trafficking.” Detective Chief Superintendent John Cuddihy, head of Police Scotland’s Organised Crime and Counter Terrorism Unit, said: “This is a superb result for all the agencies involved in this operation. This successful operation is a shining example of the strong partnerships that Police Scotland have with the National Crime Agency and others nationally and internationally.

“The new Scottish Crime Campus in Gartcosh, where we are co-located with the National Crime Agency, provided a significant number of specialist officers and resources to assist with the operation, and we are more than happy to co-operate with other law enforcement agencies to successfully tackle and disrupt serious and organised crime at all levels.” Analysis of computers seized at Van Doesburg’s home connected him to the Cape Maria. There were 84 references to the ship in the memory of a laptop, 1,844 references to Hunterston and 208 to the ship’s home port Santa Marta.

Further inquiries highlighted the Cape Maria made previous trips to the United Kingdom in January and March. On the second of those occasions, all four men based themselves in north Lincolnshire close to where the ship was moored near to the port of Immingham.

The computers also contained references to two other ships – the Indian Friendship and the Florentina. There were 2,078 mentions of the Indian Friendship alone.

The Rotterdam HARC Team found 148 kilos of cocaine concealed in the rudder area of the Indian Friendship while it was in Rotterdam on April 21. The ship continued its on journey to the port of Hull, anchoring off the port on April 25. On May 1, it moved a short distance down the Humber to Immingham and stayed there until 4 May.

NCA investigators viewed hours and hours of CCTV footage to evidence that the four men had travelled to the UK and established themselves in Cleethorpes – less than 10 miles away from Immingham. Van Doesburg was unaware the cocaine had already been found on the Indian Friendship.

Van Doesburg and Van Milt arrived on April 29 on the Rotterdam to Hull ferry and were in a vehicle that was towing the boat. They visited a B&Q in Grimsby to buy tools before booking into a hotel in Cleethorpes. On May 1, they picked up Roderick and Darryl-Jay from Leeds Bradford Airport. RNLI lifeboat officers saw some of the men regularly going out to sea in their boat.

After dropping Van Doesburg at Leeds Bradford Airport on May 5, the others headed for Scotland and stayed in hotels in the Largs area. CCTV showed them visiting a Halfords store in Greenock to buy camping equipment and C&C Marine Services in Largs to enquire about hiring diving equipment.

Van Doesburg and Van Milt were also linked to cocaine found on the Florentina ship on 22 March. The HARC team found 123 kilos of cocaine in the control room. Officers spotted them near to a rubber dinghy on a trailer that was stuck in the sand.

During the investigation the NCA has also received support from the CPS Organised Crime Division, the Crown Office and Procurator Fiscal Service, and West Yorkshire Police.