In their day-to-day operations the intelligence and security Agencies operate under the immediate control of their respective Heads. Each of the Heads has a statutory duty to provide annual reports on the work of their Service to the Prime Minister and to their Secretary of State, and brief their respective Secretary of State regularly.
The Prime Minister has overall responsibility for intelligence and security matters. He is accountable to Parliament for matters affecting the Agencies collectively.
The Home Secretary is responsible for the Security Service; the Foreign Secretary for Secret Intelligence Service and GCHQ; and the Defence Secretary for the Defence Intelligence Staff.
Following an internal review [PDF 15 pages 240KB], a new sub-Committee on Intelligence, chaired by the Prime Minister, began work in September 2009. Click here to see the membership and terms of reference for the Committee. It is supported by a committee of senior officials from the relevant departments, and the heads of the intelligence agencies. This Committee is chaired by the Cabinet Secretary.