The British classification marking STRAP

(Updated: November 26, 2014) Most of the documents leaked by Edward Snowden are from the American signals intelligence agency NSA , but there are also quite a number from their British counterpart GCHQ . Documents from both countries are classified as TOP SECRET and often have additional markings to further restrict their dissemination. Where on American documents we see markings like COMINT (Communications Intelligence) and NOFORN (No Foreign Nationals), the British have the mysterious term STRAP followed by a number. Information about American classification and dissemination markings can rather easily be found on the internet (see also The US classification system on this weblog), but there are hardly any details about the British classification system. But luckily, there's one source available which describes STRAP and other British classification practices in detail: the extensive Defence Manual of Security from 2001. Chapter 17 (page 1131-1135) of Volume 1 gives an overview...