A Royal Navy patrol ship has escorted three Russian warships as they travelled through the English Channel.
The incident involving Portsmouth-based HMS Mersey and a Wildcat helicopter from RNAS Yeovilton is the third time in two months that the Royal Navy has been scrambled to keep a watch on Russian vessels passing the UK.
A Royal Navy spokesman said the Russian spy ship Fyodor Golovin, landing ship Alexander Ostrovsky and tanker Yelnya have been supporting Russian operations in Syria and were believed to be returning to their base ports in the Baltic and Barents seas.
He added: "Portsmouth-based Mersey and her 34 crew broke off from a regular fishery protection patrol in home waters and sailed to meet the Russian trio as they approached the Channel, taking over from the French Navy which has monitored the task group's progress through the Bay of Biscay.
"The patrol ship has spent 72 hours tracking the Russians as the vessels made their way into the North Sea, handing over to the Dutch Navy once the three ships had passed through the Strait of Dover."
Lieutenant Alexandra Karavla, the patrol ship's executive officer, said: "Ships like HMS Mersey are the eyes and ears of the Royal Navy around the UK, we are at sea for 320 days a year, so Mersey provides the Navy with a ship ready to respond at short notice like this.
"Although her routine business is patrolling UK waters and helping to enforce fishery legislation, HMS Mersey was tasked to locate, meet and escort the ships through the English Channel.
"In this we have been well supported by a Royal Navy Wildcat from 815 Naval Air Squadron and by Nato colleagues. Operations like this would not be possible without such support and co-operation.
"This tasking proves why HMS Mersey is vital to UK Defence. The flexibility and options these offshore patrol vessels provide to the Government is evident in the variety of tasking undertaken."
Able Seaman Ryan Flynn, a warfare specialists who has been tracking the Russian ships' progress, said: "Exciting operations like these are why I joined the Royal Navy. I love these ships because one day I will be conducting
a fishery protection boarding and the next day I will be following Russian warships off the South Coast. It's the best job in the world."
At the beginning of the year, frigate HMS Westminster was dispatched to keep track on the activities of two Russian frigates and their support vessels returning to the Baltic after operations in the Middle East, while HMS St Albans monitored the new Russian warship Admiral Gorshkov at Christmas.