SWP stands for the Socialist Workers Party, a small, far-left political party in Britain. It has never won seats in Parliament, and that is not really how it works: its influence comes from being present — its members turn up at demonstrations, marches and picket lines, and sell their newspaper, Socialist Worker, on the street. If you visit Britain and see people at a protest holding identical printed placards, they very often come from the SWP. British people mention the party mostly in connection with protest politics, and the mention is often dry or joking, because the placards and the newspaper-sellers are such a familiar sight. Two honest cautions. Letters like these carry different meanings in different places — SWP is also the name of an American party of the same kind, and the letters stand for other things entirely outside politics — so context tells you which is meant. And this is a real organisation people hold strong opinions about; a dictionary entry describes what it is, not whether it is good.

（英國）社會主義工人黨；極左小黨，以參加示威、街頭賣《Socialist Worker》報聞名