United Kingdom Parliamentary constituencies

There are 650 constituencies in the United Kingdom, each electing a single Member of Parliament to the House of Commons every five years.Voting last took place in all 650 of those constituencies at the United Kingdom general election on 7 May 2015. 330 are held by the Conservative Party, 229 are held by the Labour Party, 54 are held by the Scottish National Party, 9 are held by the Liberal Democrats, 8 are held by the Democratic Unionist Party, and the balance held by various smaller parties, none of whom have more than 4 seats, as well as 4 seats held by unaffiliated MPs. In addition there is the constituency of the Speaker, which by tradition does not belong to any party.

The number of seats rose from 646 at the 2005 general election after proposals made by the boundary commissions for England, Wales and Northern Ireland were adopted through statutory instruments. Constituencies in Scotland remained unchanged, as the Boundary Commission for Scotland had completed a review just before the 2005 general election.