Wikipedia
Belper is a town and civil parish in the local government district of Amber Valley in Derbyshire, England, located about north of Derby on the River Derwent. As well as Belper itself, the parish also includes the village of Milford and the hamlets of Bargate, Blackbrook and Makeney. As of the 2011 Census, the parish had a population of 21,823. Originally a centre for the nail-making industry since Medieval times, Belper expanded during the early Industrial Revolution to become one of the first mill towns with the establishment of several textile mills; as such, it forms part of the Derwent Valley Mills World Heritage Site.
Belper is a former constituency in the UK Parliament. It was created at the 1918 general election as a county division of Derbyshire, comprising the area in the centre of the county and surrounding Derby, and named after the market town of Belper although this was in the north of the constituency. In 1950 it was expanded to include the far south of the county. It was a marginal constituency for most of its existence.
The area had an ever-expanding population after 1945 as prosperous suburbs of Derby were built outside the city boundaries. Lord George-Brown, who represented the seat at the time, wrote in 1971 after his defeat in the 1970 general election that "The electorate had increased by over 10,000 since 1966, mainly from the growth of middle-class housing estates, so that most of the new electors could be expected to vote Tory. Since my majority in 1966 was 4,274, an influx of 10,000 new voters, mainly Tory, obviously imperilled the seat."
In fact, a Boundary Commission report issued in 1969 had recommended changes which would have removed the extra voters, but the Labour government of the time had delayed implementation of the report.