Number of seats in the House of Commons since 1801

The United Kingdom is currently divided into 650 parliamentary constituencies. One MP in the House of Commons represents a single constituency.

Recent reviews of parliamentary constituencies

Parliamentary constituency boundaries are reviewed periodically. The 2024 general election in the UK was contested on a new set of boundaries that resulted from the 2023 periodic review of Westminster constituencies. The total number of seats, and so the total number of MPs, was not changed from the number set by the fifth periodic review of Westminster constituencies that was conducted between 2000 and 2007.

The allocation of seats between each of the nations of the UK is based on the proportion of the UK registered electorate. For the 2024 general election:

• the allocation for Northern Ireland was unchanged
• the allocation for England increased by 10
• the allocation for Scotland decreased by two
• the allocation for Wales was reduced by eight (from 40 to 32), ending the overrepresentation of Wales 25 years after devolution

Section 3 of the Parliamentary Constituencies Act 1986, as amended, determines the frequency of constituency reviews. Currently, reviews should occur every eight years. For more information on boundary reviews, see the Commons Library briefing Constituency boundary reviews and the number of MPs.

Historic changes to parliamentary constituencies

The Acts of Union 1800 merged the separate British and Irish parliaments into a single Parliament of the United Kingdom, with effect from 1 January 1801. The first House of Commons of the United Kingdom comprised 658 members: all 558 members of the former Parliament of Great Britain and 100 members of the former Irish House of Commons. In the 19th century, changes were linked to the disenfranchisement for corruption of constituencies and to the re-allocation of seats. Following the Redistribution of Seats Act 1885, most constituencies by law returned a single MP to Parliament, although 23 constituencies, including the City of London and Bath, returned two MPs until 1910.

The redistribution of seats that occurred in 1917–18 was based on population and resulted in the number of seats in the House of Commons increasing to 707. The creation of the Irish Free State in 1922 resulted in the number of seats in the House of Commons reducing from 707 to 615. There was subsequently a steady increase in the number of parliamentary constituencies until the end of the 20th century, from 625 in 1950, to 659 in 1997. The number of seats remained at 659 until 2005. In 2005, the number dropped to 646. This followed the re-establishment of the Scottish Parliament and the associated reduction in the number of Scottish seats in Westminster. In 2010, the number of seats was increased to 650, the current number.

Information in the Excel file

The downloadable Excel file includes two tables:

• Table 1 lists the number of seats contested in general elections to the House of Commons between 1801 and the present day.
• Table 2 provides details of legislation amending the number of seats in the House of Commons. Source details are available in the Excel file.

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Please get in touch with us at papers@parliament.uk with comments, corrections, or if you would like to access the data in a different format.