The 43 Group was a British anti-fascist group set up by Jewish ex-servicemen after the Second World War. They did this when, upon returning to London, they encountered British fascist organisations such as Jeffrey Hamm's British League of Ex-Servicemen and later Oswald Mosley's new fascist party, the Union Movement. The activities of these fascist groups included antisemitic speeches in public places, and from the rank-and-file fascists, violent attacks on London Jews and Jewish property. Group members broke up far-right meetings, infiltrated fascist groups, and attacked the fascists in street fighting.

British Jews are British citizens who are Jewish. The number of people who identified as Jews in the United Kingdom rose by just under 4% between 2001 and 2021.