The anti-fascists prevented the British Union of Fascists from demonstrating at the Hyde Park in London. After a major campaign in the previous weeks, people came together to prevent the act of fascists led by the famous leader Oswald Mosley. 20,000 people believed that the way to the extreme right had to be closed, who were faced with 3,000 fascists. We consider the decisive struggle of the anti-fascist movement against the BUF to delegitimize that party that was Mussolini's model and understand its political failure.