A photograph of children on a float in a May Day procession in Plymouth, Devon, taken by an unknown photographer for the Daily Herald newspaper on 3 May, 1935.

A photograph of children on a float in a May Day procession in Plymouth, Devon, taken in May 1935 by an unknown photographer for the Daily Herald.

These children, wearing sashes bearing the names of different countries, are highlighting the call for world peace. Their float banner reads, 'Nations of the World Unite'. The 1930s saw conflict that the League of Nations - forerunner of the United Nations - was unable to contain. Pacifism had strong support within the western democracies, with many remembering the horrors of world war one. In Paris, 1889, the International Working Men's Association declared May Day a holiday for the workers of the world. Socialists, trades unions and labour movements have continued to celebrate May Day ever since.