Giving more details on the vessel, Healey said: “It is part of a Russian fleet designed to put and hold our undersea infrastructure and those of our allies at risk.
“It isn’t just a naval operation. It’s part of a Russian programme driven by what they call the Main Directorate of Deep-Sea Research, or GUGI, and this is designed to have capabilities which can undertake surveillance in peacetime and sabotage in conflict.
“That is why we’ve been determined, whenever the Yantar comes into British wider waters, we track it, we deter it and we say to Putin we are ready, and we do that alongside allies.”
He said this was a demonstration of Britain’s capability and “readiness to act”.
The defence secretary issued a warning in January about the ship after it was spotted in UK waters.
