Question to the Ministry of Defence:

To ask the Secretary of State for Defence, what his policy is on procedures to provide nuclear submarine commanders on distant patrol with information to determine the legality of an order to fire a nuclear missile.

The United Kingdom would not use any of its weapons, whether conventional or nuclear, contrary to international law. Only the Prime Minister can authorise the firing of nuclear weapons, with legal advice contributing to that decision, and the Commanding Officer of the ballistic missile submarine must confirm that the authorisation to fire meets the rigorous authentication processes in place.

We will not comment on the details of our submarine operations - including these authentication processes, what information is provided to the submarine and how information is provided to the submarine - for the purposes of safeguarding national security.