In 1919, inspired by the Bolshevik revolution in Russia, British workers took more strike action than ever before. But communists in Britain had still not formed a united party. Labour's representation in Parliament was weak.
There were similar workers' mobilisations around Europe, rebellions in the British and other empires' colonies, and soviet republics declared in Bavaria, Hungary and elsewhere. All were, in the end, defeated. But only in the end.