Juvenile jazz bands are a type of children's marching band

Marching band

Marching band is a physical activity in which a group of instrumental musicians generally perform outdoors and incorporate some type of marching with their musical performance. Instrumentation typically includes brass, woodwinds, and percussion instruments...

 that started in the 20th century almost exclusively in working class

Working class

Working class is a term used in the social sciences and in ordinary conversation to describe those employed in lower tier jobs , often extending to those in unemployment or otherwise possessing below-average incomes...

 mining areas of the North of England and the Midlands, with a few bands in the mining areas of Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

. Historically, the bands originated in the tradition of coal miners' union marches and colliery brass bands. It was felt that the children should be allowed to participate, and the earliest bands were the children's section of trade union parades.