A Russian warship, shadowed by a Royal Navy vessel, carried out a live-fire artillery exercise just 40 nautical miles south of Plymouth on Monday.

The Royal Navy monitored the exercise and is continuing to "track the vessel's activity closely", a Ministry of Defence (MoD) spokesperson said.

The Russian frigate, Neustrashimy, was also being monitored by a French military aircraft which made radio contact with the warship asking it to clarify its intentions, the BBC has been told.

Prior to opening fire, the BBC was also told that the Russian warship informed the Royal Navy Offshore Patrol Vessel, HMS Tyne, of its intention to conduct gunnery activity.

The Russian warship requested that that HMS Tyne reposition to a safer distance, which it did. The Russian live-fire exercise took place in international waters and lasted for 30 minutes.

The incident will be a reminder for the new prime minister of increased Russian naval activity near UK waters in recent months. UK defence sources would not comment on whether the incident might have been timed to coincide with the start of Andy Burnham's premiership.

Last month, Royal Marine Commandos boarded a Russian "shadow fleet" oil tanker in the English Channel in a six-hour operation which was the first of its kind by UK armed forces.

Also in June, a British couple in international waters in the English Channel came across a Russian warship - Admiral Grigorovich - 23 miles (37km) off the Isle of Wight.

The frigate fired warning shots as Jane and Alan Kelvey sailed their yacht on what Russia's defence ministry said had been a "dangerous approach". However, the couple said they were "not on a collision course".

Russian warships regularly pass through international waters in the Channel, which are separate from UK and French territorial waters.

Additional reporting by Ella Kipling