The Russian ambassador to the UK says Moscow poses no threat to Britain but did not deny allegations that his country has hidden sensors in waters around the UK to try to track the Royal Navy’s nuclear submarines. In an interview for BBC One’s Sunday with Laura Kuenssberg, Andrei Kelin said “no” when asked whether he objected to the claims.

"I am not going to deny it, but I wonder whether we really have an interest in following all the British submarine with very old outdated nuclear warheads... all these threats are extremely exaggerated,” he said. When pressed further by the BBC journalist, Mr Kelin said he did not deny there are threats facing the UK but played down concerns over Russia. He said: “This threat has been invented, absolutely, there is no threat at all from Russia to the UK."

It comes after a report in The Sunday Times that claimed Russian sensors suspected of attempting to gather intelligence on Britain’s four nuclear-armed Vanguard-class submarines were found in waters around the UK.

The newspaper reported the devices were found by the British military and considered them a potential threat to national security.

It is being viewed as part of Russian “grey-zone” tactics that can be defined as hostile activities that fall below the threshold of armed conflicts, such as cyber-attacks or damage to infrastructure like energy pipelines.

Since Russia’s full-scale invasion of Ukraine, the Baltic Sea has seen a series of incidents in which power cables, telecom links and gas pipelines have been damaged.

Many of the incidents have been blamed on Russia, which has denied the allegations.

In January, the Royal Navy tracked a Russian spy ship, the second time it had entered British waters in a matter of months.

Defence Secretary John Healey revealed the Yantir had been detected “loitering” over critical undersea infrastructure in November and said he ordered a Royal Navy attack submarine to surface close to the ship in a rare warning.

He added the vessel then left UK waters “without further loitering”.

Last week, former defence minister Tobias Ellwood told The Guardian the UK is “behind the curve” in tracking Russia’s deep-sea operations.

A Ministry of Defence spokesperson told the BBC the UK is committed to “maintaining and enhancing the security and resilience of critical undersea infrastructure”.