Two Turkish sailors convicted of smuggling a record £512 million worth of cocaine aboard a tug boat are to appeal against their conviction.

Mumin Sahin and Emin Ozmen were each jailed for at least 20 years following trial after three tonnes of the Class A drug were discovered inside the MV Hamal about 100 miles off the coast of Aberdeen in the North Sea.

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

READ MORE: Drug smugglers jailed for 42 years in £500m cocaine haul off the coast of Scotland

Ship's captain Sahin, 47, was sentenced to 22 years while second captain Ozmen, 51, was given a 20-year term at the High Court in Glasgow earlier in August.

Glasgow Times:

Charges against four other men were found not proven.

READ MORE: Drug smugglers jailed for 42 years in £500m cocaine haul off the coast of Scotland

A High Court official confirmed Sahin has intimated his intention to appeal against conviction and sentence, and Ozmen against conviction.

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

Investigators drilled through a steel plate into a secret compartment to find 128 bales of cocaine weighing 3.2 tonnes which took nearly three days to remove.

READ MORE: Drug smugglers jailed for 42 years in £500m cocaine haul off the coast of Scotland

The entrance was found under a wardrobe with the opening cemented over - one of the most intricate concealments the Border Force has ever encountered.

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.