The most unusual subject files in this release are in KV 3/72-73, which concern a collection of records illicitly removed from the Reichsministerium archives in Germany in 1921 by an agent of the British Army of the Rhine. Some original documents remain on the files, including lists of wartime German spies in Poland, Russia and Macedonia and lists of agents used by the Berlin Intelligence Centre. One of the files concerns the activities of German spy Friedrich Katsch, who spied on Britain from Stockholm in 1915. The seized files themselves are in KV 3/72, while translations and summaries, and some contemporary assessments of the accuracy of German intelligence, based on comparison of figures drawn from the files with British documentation, are in KV 3/73, covering 1921-1922.
KV 3/75 (1943-1951) deals with Security Service research into German penetration of allied intelligence organisations (principally SOE and the Secret Intelligence Service) during and after the war. The file was initiated following concerns about the increasing number of allied escapees arriving in Britain in 1943, of which at least two admitted to having been freed by the Germans in order to carry out espionage missions. The Director General called for an interim report, which was completed by Mr Curry of the Research Department, and is on the file. It covers a number of penetration cases, including several Belgian, French and Norwegian ones. While the report recognises that the internal SOE investigation of German penetration of its Dutch network was under way, the report does not go into details. The report highlighted real concerns (Lt Col Robertson minuted on seeing it "when all the evidence is collected together like this, the picture presented is not a reassuring one") - but any action resulting from it is recorded on other files. There is a further flurry of action on the file dating from 1951 when a Spanish newspaper published articles on German penetration of SOE in Holland derived from the booklet Schreieder und die Spione, a copy of which is on the file.
KV 3/76-77 are concerned with German intelligence objectives in the UK from 1939, and include various situation reports, analysis of tactics and techniques, and include photographs of some agents. KV 3/76 (1941-1942) includes analysis of German objectives and the German organisation for sending agents into Britain compiled from confessions of captured enemy agents, intercepted messages and other information. The file includes a map of enemy entry routes, photographs of German wireless transmitters and code sheets and wheels, and photographs of a number of captured agents. KV 3/77 makes a detailed assessment of German intelligence objectives in Britain in March 1942, and looks at the way in which the agents were paid using Bank of England notes. There is a hand-drawn map showing areas of German agent activity in Britain in October 1940.