Defence of the Realm Act and Wartime Surveillance

The Defence of the Realm Act was introduced at the opening of the First World War and repeatedly expanded. It allowed the government to control communications, censor publications, regulate civilian conduct, requisition property and create new wartime offences.

Police and intelligence agencies used emergency powers to investigate pacifists, conscientious objectors, labour activists and suspected enemy agents. The boundary between military security and political repression became increasingly difficult to define.