Question to the Ministry of Defence:

To ask the Secretary of State for Defence, what steps he is taking to ensure that Britain's nuclear submarine fleet systems have robust and up-to-date operating systems installed in place of Windows XP.

We continually assess the capability of the United Kingdom's nuclear submarine fleet to ensure its operational effectiveness and to maintain resilience against potential threats.

I am withholding information on the specific systems used by our submarines as disclosure would, or would be likely to prejudice the capability, effectiveness or security of our Armed Forces.