Directors-general of the Security Service (MI5) (19092008)
The Security Service was founded in October 1909 as the home section of the Secret Service Bureau and was renamed Military Intelligence section 5 (MI5) in 1916. The service was established to counter German espionage in the UK and was initially headed by an army officer, Captain Vernon Kell, and Captain Mansfield Cumming
of the Royal Navy. Kell and Cumming divided the service's responsibilities into separate organizations: the former focused on countering foreign espionage within the UK; the latter (which became the Secret Intelligence Service) on intelligence gathering overseas.
Until 1993 directors of the Security Service (as it became in 1931) were appointed in secret by the prime minister and not named publicly, a policy that ended during Stella Rimington's directorship.