Photograph showing forged documents for Edward Chapman (Agent Zigzag), 1945 (Catalogue reference: KV2-462)

This is a brief guide to researching British government records on security history. Security history records are wide-ranging and can sometimes be complicated. Not all records are available to the public and not all survive. Of those that are open to the public, most are available at The National Archives. This guide will help you gain a general overview of the main sources of the information that exists, and where to find it.

  • What records can I see online?

    • Security Service miscellanea

      Search Discovery, our catalogue for selected Security Service documents which have been made available digitally. Use selected keywords and phrases, such as "security service" (in speech marks), to help narrow down your search.

  • What records can I find in other archives and organisations?

    • Consultative Group on Security and Intelligence Records

      Vist the webpages of the Consultative Group on Security and Intelligence Records for further help and guidance on intelligence-related records. This group is specifically set up to help the official, archival and academic communities with security and intelligence related material.

  • What other resources will help me find information?

    • Websites

      Browse the history and records section of the Secret Intelligence Service (MI6) website for information on the organisation's history and records policy.


      Browse the Security service (MI5) website for more information about the organisation.


      Browse the history section of the Government Communications Headquarters website for more information about the organisation's past.

    • Books

      Search The National Archives' bookshop to see whether any of the publications below may be available to buy. Alternatively, look in The National Archives' library catalogue to see what is available to consult at Kew.

      British Intelligence by Stephen Twigge, Edward Hampshire and Graham Macklin (The National Archives, 2008)

      The Defence of The Realm: The Authorised History Of MI5 by Christopher Andrew (Penguin, 2009)

Did you know?

The United Kingdom has several intelligence and security services, collectively known as the Agencies. These are separate from Police agencies such as the Special Branch or the Anti-Terrorist Branch (SO13) which have now merged to form Counter Terrorism Command (also known as SO15).

The Secret Intelligence Service (MI6) was founded in 1909 as the Foreign Section of the Secret Service Bureau and is responsible for gathering intelligence overseas. MI6 is a child agency of the Foreign and Commonwealth Office. Most records of MI6 are not available to the public.

The Security Service (MI5) began in 1909 as the domestic arm of the Secret Service Bureau. It is responsible for protecting the country against external threats to national security, which include terrorism, espionage and the proliferation of weapons of mass destruction. MI5 belongs to the Home Office.

The Government Communications Headquarters (GCHQ) began as The Government Code and Cypher School (GCCS) in 1919. It is responsible for providing signals intelligence for government and for the prevention and detection of serious crime. GCHQ is the responsibility of the Foreign and Commonwealth Office.

MI5, MI6 and the GCHQ work alongside each other and come under the direction of the Joint Intelligence Committee (JIC). They also work alongside the Defence Intelligence Staff (DIS) in the Ministry of Defence.

Try browsing with a specific term, name or subject to help focus your search. Keywords such as "security service" (in speech marks) may be useful. Remember, there is likely to be some overlap between separate series on any given subject or event. For example, a decision made during a conflict may have been informed by the Security Service (KV) and the Foreign Office (FO) and then discussed by the Cabinet (CAB) and Prime Minister (PREM) before being carried out by the Ministry of Defence (DEFE).