A vessel measuring over 200 metres sighted on the horizon from Wick Bay yesterday afternoon was confirmed to be a specialist supply ship supporting the Royal Navy (RN).

A Royal Navy spokesperson said: "It's a Tide-class Royal Fleet Auxiliary (RFA) support ship [and] provides logistical support to the Royal Navy all over the world."

Four of these fast fleet vessels entered service with the RFA in 2017.

William Munro of Caithness Seacoast Ltd , based in Wick, provided extra details and said that his sources informed him that the vessel is still in the area and reported as being the RFA Tideforce (No. 139).

"She is a civilian [Merchant Navy] support vessel for the Royal Navy. It would be not correct to refer to her as a tanker," said Mr Munro.

"The vessel does have liquid fuel carrying capacity for the RN fleet but is far more versatile regarding the carrying of supplies and materials," he added.

Mr Munro said that working as a "semi-retired oil tanker captain" he had occasionally carried diesel and jet fuel for the UK and Nato armed forces from and to various bases around the UK and Europe.

The 37,000 tonne RFA ships provide fuel, food, fresh water, ammunition and other supplies to RN vessels around the world.

They have 17 separate tanks which can hold 19,000 tonnes of F76 marine diesel, F44 aviation fuel and a further 1300 tonnes of fresh water.

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In addition, they are fitted for two 20mm Phalanx close-in weapon systems and two 30mm cannons as well as light machine guns and minigun positions for force protection.

The huge ship, which was sighted east of Wick Bay at around 3.30pm yesterday, also appeared to be carrying a Merlin helicopter on board.

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