The Corn Laws were repealed after militant action by the Anti Corn Law League which began in Manchester in 1839.
They said that the Laws were a subsidy and increased the cost of industry.
The Corn laws were seen as a privilege of wealthy landowners and the repeal reduced not only the income of crops but the political power that landownership represented. http://www.spartacus.schoolnet.co.uk/PRanticor n.htm