The newly-declassified documents include details about some of the UK's most notorious spies.

Secret UK Files Detailing Confessions of Cambridge Five Spies Released By Michael Holden LONDON ... Cairncross, the last of the spy ring to be publicly identified in the 1990s, admitted in a 1964 interview in the U.S. that he too had been recruited ...

A World War II-era tailing guide is among declassified records shedding light on spy game in MI5: Official Secrets, at the National Archives.