1940 – 1948

Zionist Terrorism

After World War II, the main threat to UK national security came from Zionist terrorist groups including the Stern Gang and the Irgun, who’s aim was to create an independent Jewish state. The UK, holding the mandate for Palestine, faced assassination attempts and escalating violence, especially after 1945. In 1946 the Irgun bombed the British administrative headquarters for Mandatory Palestine at the King David Hotel in Jerusalem, claiming the lives of 91 people and injuring 46. MI5 and Special Branch whose responsibilities included monitoring domestic extremist activity and conducting surveillance, investigated Zionist extremists using telephone intercepts and Signals Intelligence (SIGINT). This lead to identifying UK-based suspects and thwarting several bomb attacks in the UK, including letter bombs sent to British officials.

Whilst the groups could not sustain a terror campaign in Britain, attacks in Palestine continued until the British Mandate ended in 1948.