The 8,000-ton Russian destroyer Vice Admiral Kulakov and her supporting tanker were returning from the eastern Mediterranean after supporting Russia’s campaign in Syria.
Late last week they passed through the English Channel on their way to their home port of Murmansk in Arctic Russia.
But on Saturday as they sailed off eastern Scotland a 5,000 tonne Royal Navy frigate was ordered to shadow and escort the Russian pair.
HMS Somerset followed them from the Moray Firth off Inverness up to the Norwegian coast.
She had been carrying out sonar trials in the North Sea when the order came through to find and track the Russians.
HMS Somerset’s Commanding Officer, Commander Timothy Berry, said: “As with all Royal Navy ships operating in UK waters, HMS Somerset was at a high state of alert to deal with any maritime security task such as this.
“Monitoring transits of non-NATO warships through UK territorial waters is part of what the Royal Navy does all year round to keep Britain safe.
“We now continue with our original tasking having seen the Russian ships safely through the UK’s area of interest.”
The Kulakov is no stranger to British waters.
She paid an official visit to Portsmouth in 2012 and took part in commemorations of the Battle of the Atlantic in Liverpool in 2013.
But since then, tensions between Britain and Russia have heightened, particularly after president Putin annexed the Crimea from the Ukraine in 2014.
Russian warships and warplanes have increased their activity, probing the UK’s defences at almost Cold war levels.
And in March last year HMS Somerset shadowed the Kulakov, also in the Moray Firth.
Russia has this year put Britain’s responses to the test by repeatedly putting warships and submarines through the English Channel.
In May the diesel-electric submarine Krasnodar sailed through the sea and was shadowed through the Straits of Dover by HMS Somerset.
The previous month Somerset’s sister ship HMS Sutherland escorted two Russian warships as they sailed close to UK territorial waters.