British Jews “infiltrated” some of the most violent fascist groups and rallies during the 1930s, passing evidence to Scotland Yard, according to newly available Board of Deputies archives.

The Board’s defence division has transferred 27 years’ worth of archives to the Wiener Library because of the significance of the documents — which showed information passed from Jewish operatives to Scotland Yard was crucial in turning influential opinion against Oswald Mosley’s fascists, and the passing of the Public Order Act 1936, which banned private political armies.

Deputy Monty Kolsky and Ajex leader Peter Russell first came across the archives while working at the Community Security Trust.