The National Archives currently hold more than 5,000 historical Security Service files, covering a period up to 1958. We are continuing to release files on a regular schedule, usually about every six months.
You can search for specific words and phrases contained in descriptions of released Security Service files using the form on the National Archives website. (This search form does not search the contents of files, only their descriptions.) Files can be ordered online and examined at the National Archives by pass holders, free of cost. See the National Archives website for more information on how you can become a pass holder and how to get to the National Archives building at Kew.