The collection includes: McLachlan's papers for "Room 39"; Beesly's papers for "Very Special Intelligence" and for "Very Special Admiral"; and papers of Commander Lloyd Hirst, an intelligence officer.

British Intelligence Objectives Sub-committee and Combined Intelligence Objectives
Sub-committee reports on German and Japanese war industry.

Consisting of intelligence from intercepted enemy communications, forwarded from the Admiralty to Allied Commands, "Cairo Series", June 1942-September 1943.

Generally being decrypts from the Government Code and Cipher School at Bletchley Park, Buckinghamshire, using the Enigma machine. The Enigma signals were given a special security classification, "MSS" (Most Secret Source) or "ULTRA".

This collection consists of letters and accounts of Denniston's code-breaking work in Naval Intelligence in both World Wars and of the setting up of Room 40. There are several photographs of Denniston in Naval uniform and some of the Royal Naval College at Osborne.

The Wilkinson Papers include three war journals, official telegrams and several files of official correspondence, and provide an extremely valuable record of British Intelligence in the Far East in the Second World War.

Papers relating to Mavis Batey's work at Bletchley Park. The collection is mainly comprised of later articles and notes for speeches by Batey including memories about her work and her colleagues, and a small amount of correspondence with historians of intelligence. Also includes copies and transcripts of wartime documents.

This collections comprises correspondence; papers relating to awards and honours; wartime documents including copies of the Air Scientific Intelligence reports he wrote during WWII, copies of intelligence reports he received, and captured German documents; papers relating to Jones' research topics and scientific interests; publications; conferences, lectures, and speeches.

Comprising official papers, correspondence and notebooks mainly relating to Norway and Finland.
The papers focus on Rowland Kenney's work in Norway during the two World Wars and on Kit Kenney's work in Finland and Norway during the Second World War.

These papers mostly consist of correspondence and articles. The papers all deal with intelligence matters such as access to wartime records, claims of espionage, memories of wartime code-breaking-related activities and publications by former Bletchley Park staff or about Bletchley Park.

The collection comprises the redacted and edited typescript copies of Mitrokhin's original manuscript notes of documents from the KGB archive. All documents are in Russian.

The papers relate to the setting up of Room 40 and the Naval Intelligence's code-breaking activities in the First World War and to Clarke's service in the Government Code and Cypher School from 1922 to 1945.