History

Since its establishment in 1909, the Security Service and its predecessor organisations have worked to protect the United Kingdom from a range of threats such as subversion, espionage and terrorism.

Its work requires a great deal of secrecy. It is only in recent years that a policy of carefully controlled openness has been adopted to put into the public domain information about the Service's work and the issues that we face, while ensuring that we continue to protect our sources and techniques.

This section of the Service's website explains the origins, history and development of the Service from its foundation through to the present day. It also provides information on how you can learn more about the Service's history.

You can find out more about the history of the Service at The National Archives (new window) in Kew, west London - see The Security Service at The National Archives for more information.

The Security Service has so far had sixteen Directors-General. You can find out about the first fifteen in Former Directors-General. Jonathan Evans is our current Director-General.

The Service has also changed its name several times over the years. See What's in a name? for a quick reference guide to our various identities.

A brief history of the Security Service

• 1909 to World War I

How and why the Service was founded; the fight against German espionage; the origins of the "MI5" name.

• The inter-war period

The creation of the Security Service; Soviet espionage in the UK; the rise of Nazism and the Service's role against fascist activity in the UK.

• World War II

Internment of enemy citizens; the "Double Cross" system; the battle for Gibraltar; GARBO and the D-Day landings; Hitler's last days.

• The Cold War

Soviet spies in Britain; the threat of subversion; the rise of the terrorist threat.

• 1990s to present

A changing role for the Security Service; a new era of openness; adapting to post-Cold War challenges.