Prevention of Terrorism Acts
The Prevention of Terrorism Acts were a series of acts of the Parliament of the United Kingdom from 1974 to 1989 that conferred emergency powers upon police forces where they suspected terrorism. The direct ancestor of the bill was the Prevention of Violence (Temporary Provisions) Act 1939 which was brought into law in response to an Irish Republican Army (IRA) campaign of violence under the S-Plan.
Source: Wikipedia — Prevention of Terrorism Acts (CC BY-SA 4.0)