The National Security Council is a United Kingdom cabinet committee. The Council's terms of reference were said in September 2022 to include matters relating to national security, foreign policy, defence, trade, international relations, development, resilience and resource security.

The powers of the prime minister of the United Kingdom come from several sources of the UK constitution, including both statute and constitutional convention, but not one single authoritative document. They have been described as "...problematic to outline definitively."