Report: Russian Sub Hit Royal Navy Frigate's Sonar Array

The UK Ministry of Defence has confirmed that a Russian submarine collided with a towed sonar array connected to the frigate HMS Northumberland during a patrol in 2020. 

The run-in was filmed by a TV crew for BBC Channel 5 who were on board for the series Warship: Life at Sea. It was not previously reported. 

"In late 2020 a Russian submarine being tracked by HMS Northumberland came into contact with her towed array sonar," the UK MoD said in a statement. "The Royal Navy regularly tracks foreign ships and submarines in order to ensure the defence of the United Kingdom."

The frigate's helicopter had spotted the sub's periscope on the surface shortly before the impact. The contact disabled the towed sonar array, forcing Northumberland to return to port, according to the BBC. 

The incident was not reported at the time. HMS Northumberland was attached to Carrier Strike Group 2 for an exercise when the event occurred, and in a statement in late 2020, the Royal Navy said only that she had called at three ports in Scotland. 

Though physical contact between NATO vessels and Russian warships was an occasional occurrence during the Cold War, the run-in is the first time that such an incident has been reported for a Royal Navy vessel since the fall of the Soviet Union. Russian submarine patrols in the North Atlantic and the North Sea have been on the rise for years, raising the chances of interactions with the Royal Navy. 

Northumberland operates a Type 2087 towed low-frequency sonar array, capable of both passive and active operations. It is manufactured by Thales, and it is designed to detect subs before they are within range of attack.