The Service operates under the statutory authority of the Home Secretary (new window), but it is not part of the Home Office (new window).
The Head of the Service is the Director General (DG), currently Jonathan Evans. He is supported by a Deputy Director General (DDG), who is responsible for the Service's intelligence and security advice, counter-espionage, counter-terrorism, counter-proliferation and matters concerning the Service's operational capabilities.
MI5 Organagram
There are seven branches within the Service, each headed by a Director.
The DG is responsible for two of these. One manages the Service's personnel and security. The other is responsible for strategy, policy, finances and facilities.
The DDG is responsible for the other five branches. Of these, one is responsible for countering international terrorism, as well as counter proliferation and counter espionage work. Another is responsible for domestic and Northern Ireland counter terrorism. A third provides advice on protective security measures to counter the various threats.
The last two branches under the DDG are responsible for managing the Service's operational capabilities such as its technical and surveillance operations, and for managing the Service's technological capability.
Both the DG and DDG are directly supported by the Service's Legal Advisors.
The Director General, the Deputy Director General, the Directors and the Legal Advisor constitute the Management Board of the Service and meet regularly to consider policy and strategic issues. The Board decides how the priorities and organisation of the Service should adapt to reflect changes to the threats. Its decisions are subject to the external validation processes described in the Governance section of this website. A separate Operating Board is responsible for the direction, co-ordination and priorities of the day-to-day business and operations of the Service.
The Management Board is supported by two Non-Executive Directors, appointed from outside the Service to enhance its decision-making by bringing an external perspective, expertise on private sector practice and a readiness to challenge existing assumptions and approaches. The Non-Executive Directors play a purely advisory role, with no responsibility for managing the work of the Service.