Surveillance Methods

Abstract

This chapter examines the surveillance methods used by the MI5. It is a curious feature of MI5’s mandate that it included nothing about the methods to be used for the purposes of the defence of the realm, which was its core task. The Security Service would obtain information about individuals and organizations in a number of ways, which might be described as volunteers who spontaneously reported fellow citizens; monitoring by Special Branch, infiltration, and the use of informers; watching and following; interrogation and questioning; and the interception of communications (mail, telegrams, and telephones); as well as the use of secret microphones hidden in various locations; and foreign security and intelligence agencies. The chapter also looks at the different circumstances in which these different forms of surveillance were used: a contrast between routine and intense surveillance; between passive and active surveillance; and between constant and periodic surveillance.