The Chiefs of Staff Committee (CSC) is composed of the most senior military personnel in the British Armed Forces who advise on operational military matters and the preparation and conduct of military operations. The committee consists of the Chief of the Defence Staff who is the chairman and professional head of the forces, the Vice-Chief of the Defence Staff, who is the vice-chairman and deputy professional head of the armed forces. The committee also consists of the professional heads of each branch of the armed forces: the First Sea Lord and Chief of the Naval Staff, the Chief of the General Staff and the Chief of the Air Staff.

The Chief of the Defence Staff (CDS) is the professional head of the British Armed Forces and the most senior uniformed military adviser to the Secretary of State for Defence and the Prime Minister of the United Kingdom. The chief of the defence staff is based at the Ministry of Defence and works alongside the Permanent Under-Secretary of State for Defence, the ministry's senior civil servant. The Chief of Defence is the highest ranking officer to currently serve in the armed forces.