Russia has quietly launched its newest nuclear submarine, the Khabarovsk, sending it for sea trials in the White Sea without official fanfare. The vessel has been built to carry Poseidon nuclear torpedoes, a weapon Moscow claims is unstoppable and capable of triggering radioactive tsunamis, and its unveiling comes amid heightened rhetoric from Kremlin-aligned media urging retaliation against Britain over its military support for Ukraine.

The 10,000-ton Khabarovsk reportedly cost around £1billion and can carry up to six Poseidon torpedoes alongside conventional anti-ship and land-attack missiles. Poseidon itself is said to have a range exceeding 6,000 miles and can dive to depths of 3,280ft, with Russian officials describing it as a "doomsday weapon" impossible to intercept. Western defence analysts, including Dr Richard Connolly of RUSI, say the claims are likely exaggerated and that Russia is unlikely to use the weapon given the certainty of retaliation from Britain's Trident nuclear deterrent.