In the 20th century the first victories of May Day began to be won with workers in different countries getting an eight-hour working day, while in some places it was agreed that May 1 should be a holiday.
When the First World War threatened, workers in different European countries tried to unite to put the ideals of May Day into practice by stopping war and preserving peace. But they were badly let down by many of their leaders.
Only in Russia, in 1917, did the workers succeed in breaking out of the grip of war and setting up a new society. The new State which they set up, the Soviet Union, became the hope of workers everywhere and May Day demonstrations in other countries pledged friendship and support.
Later in the 1930s, when Hitler came to power in Germany and his nazi State threatened a new wave of war and oppression, the May Day banners carried a new message - defeat fascism.
It took six bitter years of war 1939-45 to defeat fascism. But afterwards the world was changed with new Socialist states established, with many countries that have previously been oppressed winning their freedom and workers' organizations growing in strength.
In Britain the trade union movement grew to ten million strong after the war and each May Day has marked a new stage in workers' efforts to win a better life.
This year on May Day people all over Britain will march with colourful banners. The slogans will be many and varied. They will oppose the new law the Government is trying to bring in to restrict the freedom of the unions.*
* (In spite of the continuous protests of the workers, the Bill was passed by the reactionary Tory Government.)