Back in Britain in the 1930's, there was a divisive political leader whose rallies were beginning to cause concerns. A former political liberal, he'd taken to denouncing his previous views; at massive indoor rallies (including one at the Albert Hall), he stirred his listeners to passionate cheers by denouncing immigrants, Jews, and a shadowy cabal of forces that were driving the common man down. He love to egg on protesters at these rallies, and had special squads of "stewards" to rough them up and throw them out, but in fact they served a purpose. Indeed, he credited them with making his speeches all the more effective, even saying he looked forward to them.
The man in question was Sir Oswald Mosley. And Britons weren't quite sure what to make of him; though many despised his views, his party -- the British Union of Fascists -- was granted the same rights as any other, and in the early 1930's their polling numbers were on the rise, although they did not yet have any elected member of Parliament. Mosley, inspired by visits with Mussolini and Hitler, decided to give his party a paramilitary flavor, initially going with plain black futuristic uniforms, but later graduating to jackboots and a peaked cap (for Mosley himself at least). From their large indoor rallies, they graduated to outdoor ones with marches; when Mosley was clobbered with a flying brick by protesters at one, he wore his bandages as a cap of pride. It was part of his strategy to march directly into areas, such as the East End of London, where the bricks were most likely to fly; this both fed his sense of justified anger, and forced the police into serving as his own personal security.
Things came to a head in October of 1936; Mosley had planned a rally and march through the East End, and had pulled out all stops; his new uniform was ready, as were many of his followers, some of whom rode in specially fortified vans. The Metropolitan Police, under the leadership of Sir Philip Game, mustered out 6,000 officers, one of the largest forces since the days of the Chartist rallies in the 1840's, but even then it soon became clear they were stretched thin; attempts to disperse a crowd of nearly 100,000 East Enders proved impossible. Those opposed to Mosley, whose planned route would have taken him down Cable Street, erected barricades of bricks and sticks, along with a lorry and some construction equipment they'd procured from a nearby builder's yard. They hoped to block the march by their mere presence, though they were also prepared to fight; one witness described men wrapping barbed wire around chair-legs as improvised weapons. The chant of one and all was simply this: "They shall not pass!"
In the end, Sir Philip Game persuaded Mosley to call off that part of his plans, and to march instead back where he'd come from to Hyde Park. Public alarm over the events led to the passing of the Public Order Act, which although it did not outlaw Mosley's party, prohibited political uniforms such as those the "blackshirts" had favored. When Britain and Germany went to war, the BUF was banned, and Mosley and many of its other leaders were imprisoned for the duration. One, though, did escape: the scar-faced William Joyce, who as "Lord Haw-Haw" broadcast mocking ripostes to nearly every one of Churchill's radio speeches. After the war, Joyce was convicted of high treason, and hanged at Wandsworth Prison. Sir Oswald returned to political life, though in his one election -- for Kensington North in 1959 -- he polled only 8% of the vote with an anti-immigration platform that included deporting those from the West Indies.