Question to the Ministry of Defence:

To ask the Secretary of State for Defence, with reference to the incident involving the Belfast to Cairnryan passenger ferry and a nuclear-powered submarine in November 2018, what (a) lessons have been learned from that incident, (b) steps have been taken to ensure that nuclear-powered submarines do not travel at periscope depths on any ferry lanes on the west coast of Scotland, (c) is now the minimum clearance between ferries and submarines passing, on the surface or submerged, and (d) additional safety measures have been taken, as a result of that incident, for all ferries around the Scottish coast.

Ensuring safety at sea is a top priority for the Royal Navy. The Marine Accident Investigation Branch's (MAIB) report is welcomed and the Royal Navy fully accepts their recommendation. Actions have been taken to prevent re-occurrence and a system of assurance is in place in accordance with the Navy's Safety Management System.? To deliver the MAIB's recommendation, the Fleet Commander has directed an independent review of the actions taken to provide assurance that such actions have been effective. This review will be led by the Defence Maritime Regulator, part of the independent Defence Safety Authority.

I can confirm that there is no plan for submarines to cease operating at periscope depth.

The safe distance between a submarine operating at periscope depth and surface shipping is determined by the combined speed of the vessels at a given time, and is achieved by manoeuvring the submarine to ensure that surface vessels do not approach within the distance that the submarine would dive to a safe depth to remain safe.