Two Turkish men convicted of smuggling £500 million worth of cocaine on board a ship in the North Sea have each been jailed for at least 20 years.

Mumin Sahin and Emin Ozmen were found guilty after a trial at the High Court in Glasgow after three tonnes of the Class A drug were discovered inside the MV Hamal about 100 miles off the coast of Aberdeen.

The 2015 seizure is said to be the biggest single cocaine haul ever recovered at sea in Europe.

Read more: Two men guilty of smuggling £500 million of cocaine found inside ship

The drugs were found hidden in a specially-adapted secret hold in the Tanzanian-registered tugboat, which was sailing from Istanbul to Tenerife and then to the North Sea, when it was stopped by the Royal Navy frigate HMS Somerset and Border Force cutter HMC Valiant.

Sahin, 47, was sentenced to 22 years while Ozmen, 51, was handed down a 20-year term at the High Court in Glasgow.

Judge Lord Kinclaven told the men the quantity of drugs was "not only significant but massive" and drugs trafficking had a "devastating impact" on people and communities.

He said: "You were involved in a most serious operation of commercial scale involving the transportation of cocaine by ship, in an operation which crossed international and indeed intercontinental boundaries."

Read more: Two men guilty of smuggling £500 million of cocaine found inside ship

He told the ship's captain Sahin, he was "not at the top of the drugs tree" but had played an important role in the offence, while second captain Ozmen's role was "to some extent a lesser one".

Speaking following today’s sentencing, the Crown Agent, David Harvie said:

“The international drugs trade does not respect borders, and those of us whose job it is to dismantle it are working ever-closer together to ensure we stay one step ahead.

Read more: Two men guilty of smuggling £500 million of cocaine found inside ship

“Scotland’s reach in pursuing criminals is on a truly global scale and in this case we have dealt a substantial economic blow to organised criminals."

Officers boarded the Hamal following a tip-off from French customs body DNRED, and once it was docked in Aberdeen they drilled through a steel plate into a secret compartment to find 128 bales of cocaine weighing 3.2 tonnes, with an estimated street value of £512 million.

The entry to the space was found under a wardrobe in one of the crew's quarters, with the opening cemented over.

Sahin and Ozmen were found guilty of being concerned with the carrying and concealing of cocaine on the ship between February 20 and April 23 last year, and of being concerned in the supply of cocaine between April 21 and April 23.

The men, both first offenders who have worked in the shipping industry since leaving school, continue to maintain their innocence but accept the jury's verdict.

Charges against four other men were found not proven.

Sahin's lawyer, Jonathan Crowe, said the married father-of-two was a "glorified mule".

He said: "Someone who was involved in the transportation of the drugs. Someone who was able to captain a boat.

"In regard to the drugs hierarchy, Mr Sahin is certainly not at the top of the drugs tree but somewhere further down."

Sahin was approached about captaining the Hamal in February 2015, the court heard.

Mr Crowe said he is "devastated" about missing out on milestones for his daughter, nine, and son, 13, and "just wants to go home to Turkey".

Both men have not seen their families since being taken into custody in April 2015 as their families struggle to get visa approval.

Ozmen's lawyer, Di Moore, said he is "desperate" to see his family but knows that will "remain impossible" for the foreseeable future.

Crown Agent David Harvie said the Crown Office worked with authorities in Guyana, Spain, Denmark, Norway and the US to piece crucial evidence together.

He said: "Scotland's reach in pursuing criminals is on a truly global scale and in this case we have dealt a substantial economic blow to organised criminals."

National Crime Agency senior investigating officer John McGowan said: "Today's sentencing is the culmination of a truly international investigation into a seizure that was unprecedented in its scale for Scotland, the UK and Europe.

"Although the final destination for this haul of drugs is likely to have been mainland Europe there is no doubt in my mind that some of it would have ended up on the streets of the UK, fuelling further criminality.

"By making this seizure and putting these men behind bars not only have we protected the public but we have also caused major disruption to an international organised criminal network."

Tony McMullin, regional director, Border Force north region, said: "This was one of the most intricate concealments we've ever encountered but it was no match for our expert Border Force search teams.

"Once discovered, it took nearly three days for the team to remove all the cocaine bales from Hamal - demonstrating the scale of the operation and the ability and dedication of our officers."

Despite strong intelligence that the Hamal was carrying a large volume of drugs, it could not be boarded in international waters by the UK authorities without the permission of the Tanzanian government - something they had never previously granted.

Sue Patten, head of the Crown Prosecution Service (CPS) International Justice and Organised Crime Division, said: "Acting quickly and precisely, the CPS criminal justice adviser in Tanzania was able get permission from the Tanzanian authorities to board the boat within 24 hours of receiving the intelligence.

"Under international maritime law, the UK cannot board a vessel in international waters which is under the flag of a foreign state unless that state gives specific legal permission to do so. Without the swift actions of our criminal justice adviser, there was a high risk that the vessel may have escaped and we would never have been able to bring these men to justice."