Russian spy ship directing lasers at airline pilots near Scottish waters in 'deeply dangerous' move

John Healy said Britain “is ready” to respond, with “military options” drawn up if the vessel Yantar heads south from its existing position north of Scotland, in a warning to Russian president Vladimir Putin.

The frigate HMS Somerset and RAF P-8 Poseidon aircraft have been keeping watch on the Yantar, which is designed for gathering intelligence and mapping crucial undersea cables, after it entered wider UK waters this month.

Mr Healey said the frigate and planes had been deployed to “track this vessel’s every move, during which the Yantar directed lasers at our pilots”.

“That Russian action is deeply dangerous,” he said.

Foreign Secretary Yvette Cooper, in Berlin for a meeting with her German counterpart, said the UK would be “vigilant and determined” in its response to Mr Putin’s Russia.

First Minister John Swinney called for a “very measured approach” following the security information’s release.

"I've seen the reports about the Russian vessel and obviously it's a matter of concern that there is a presence of Russian vessels in UK waters,” he said.

"The Ministry of Defence I think needs to be open and transparent about what is known. Obviously there is an obligation to keep the country safe.”

At a Downing Street press conference on Wednesday, Mr Healey said: “My message to Russia and to Putin is this: We see you. We know what you’re doing. If the Yantar travels south this week, we are ready.”

He warned the UK was facing a “new era of threat” to its security.

The vessel, designed for gathering intelligence and mapping crucial undersea cables, is loitering off the northern coast of Scotland, having entered wider UK waters over the past few weeks.

Mr Healey told the press conference: “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.”

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In January, it emerged the Yantar was caught lurking over undersea cables and was warned off by a Royal Navy nuclear-powered submarine.

The UK and Nato allies are increasingly concerned about the risk Moscow poses to offshore cables, pipelines and other infrastructure critical to internet connectivity.

Attacks on undersea cables could cause “catastrophic disruption” to the financial and communications systems Britons rely on, the National Security Strategy Committee warned in a September report.

It comes after recent damage to undersea cables in Scotland, believed to have been caused by a fishing vessel, that has caused internet and phone service disruptions in the Orkney and Shetland islands.

The Yantar has been within the UK’s exclusive economic zone, which extends up to 200 nautical miles – about 230 miles – offshore. But the vessel has been on the edge of Britain’s territorial waters, within 12 nautical miles (13.8 miles) from the coast.

The incident with the laser is understood to have happened within the past fortnight.

Mr Healey said: “Clearly, anything that impedes, disrupts or puts at risk pilots in charge of British military planes is deeply dangerous.

“This is the first time we’ve had this action from Yantar directed against the British RAF.

“We take it extremely seriously. I’ve changed the navy’s rules of engagement, so that we can follow more closely, monitor more closely, the activities of the Yantar when it’s in our wider waters.

“We have military options ready should the Yantar change course. I’m not going to reveal those, because that only makes president Putin wiser.”

A repeat of the submarine response could be one military option on the table, or warships could follow the example of the Dutch navy, which escorted the Yantar out of the Netherlands’ part of the North Sea earlier this month.

In Berlin, Ms Cooper suggested Russia’s actions were motivated by frustration at the lack of progress in Ukraine.

She said: “Russia has failed in its military objectives over the course of this year, so as a result, what we have seen them try to do is to seek continually to escalate.”