Colonel Hugh Anthony Johnstone OBE (1 May 1931 – 30 June 2014) was a British Army officer who ended his career as the administrative head of Signals Intelligence during the 1970s.
[1] He was promoted to lieutenant in 1954, captain in 1958, major in 1965, lieutenant-colonel in 1970, and colonel in 1975.
[2] Johnstone became known when he was identified by the magazines Peace News and The Leveller as the much-publicised anonymous witness Colonel B in the ABC Trial in 1978.
[3] This led to prosecutions for contempt of court which ultimately failed in the House of Lords.
[4] The case became a great embarrassment to the Crown, due to its attempts to disguise the identities of people and well-known defence establishments .