Defence Secretary John Healey has revealed a large-scale operation took place to keep track of three Russian submarines off the British coast.
A Royal Navy warship travelled thousands of nautical miles, while RAF P8 aircraft joined and 500 personnel were sent out in response to the threat, he said.
All three subs – thought to have been scanning the seabed for vital cables and pipelines that could be sabotaged – have since left UK waters.
Healey said they were left in ‘no doubt they were being monitored’ and their ‘movements were not as covert as President Putin planned’.
He added: ‘I’m making this statement to call out this Russian activity, and to President Putin I say, we see you.
‘We see your activity over our cables and our pipelines, and you should know that any attempt to damage them will not be tolerated and have serious consequences.’
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The group included one Akula-class nuclear-powered attack submarine and two Gugi submarines which are used for research on the sea floor.
In a Downing Street press conference, Healey suggested the attack submarine may have been a decoy to the two specialist vessels during the operation, which lasted more than a month.
He told reporters he was confident there is no evidence of any damage to the ‘critical infrastructure’ where the Gugi subs were spotted.
The Defence Secretary emphasised how important these undersea connections are to the UK, as an island nation.
He said: ‘Beneath our waters lies a vast network of cables and pipelines on which our way of life depends.
‘Half the gas that heats our homes, 99% of international telecoms and data traffic, trillions of pounds of global trade each day.
‘And all the reasons that make the seabed matter so much to us are the reasons that make it the prime target for our adversaries.’
Healey’s press conference comes after the Daily Telegraph reported that a Russian warship had been sent by President Vladimir Putin to escort sanctioned vessels through the English Channel.
Two ships in the Kremlin ‘shadow fleet’ were accompanied by Black Sea fleet frigate the Admiral Grigorovitch on Wednesday, monitored by the British Royal Fleet Auxiliary tanker RFA Tideforce.
Last month, Prime Minister Sir Keir Starmer gave the Royal Navy permission to board and seize sanction-breaking ships when they enter UK waters.
However, no such action is thought to have taken place since that announcement on March 25.
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