Constituencies of the Parliament of the United Kingdom

The Parliament of the United Kingdom currently has 650 parliamentary constituencies across the constituent countries (England, Scotland, Wales and Northern Ireland), each electing a single member of parliament (MP) to the House of Commons by the plurality (first past the post) voting system, ordinarily every five years. Voting last took place in all 650 of those constituencies at the United Kingdom general election on 12 December 2019.

The number of seats rose from 646 to 650 at the 2010 general election after proposals made by the boundary commissions for England, Wales and Northern Ireland (the Fifth Periodic Review of Westminster constituencies) 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, which had resulted in a reduction of 13 seats.

Primary legislation provides for the independence of the boundary commissions for each of the four parts of the UK; the number of seats for each of the countries; permissible factors to use in departing from any old boundaries; and a strong duty to consult. The Fifth Review was governed by the Parliamentary Constituencies Act 1986. Under the Parliamentary Voting System and Constituencies Act 2011, as amended by the Parliamentary Constituencies Act 2020, the number of MPs is now fixed at 650. The Sainte-Laguë formula method is used to form groups of seats split between the four parts of the United Kingdom and the English regions (as defined by the NUTS 1 statistical regions of England).

## Overview

The table below gives the number of eligible voters broken down by constituent country, including the average constituency size in each country.

### Geographical size of constituencies

Size of electorate in each constituency
As the number of electors in each constituency is similar, the constituencies themselves vary considerably in area, ranging from Ross, Skye and Lochaber, which occupies a sixth of Scotland, to the densely populated London constituency of Islington North.

Largest and smallest constituencies by UK nation
 Scotland
 Wales
 Northern Ireland

## Parliamentary constituencies in the United Kingdom

For MPs elected in the latest election (also with nominal party holding the seat in the previous election), see List of MPs elected in the 2019 United Kingdom general election.

The "Region" of the table refers to the NUTS 1 statistical region of England, which coincides with the former European Parliament constituency in which the constituency was included until 31 January 2020.

As of the 2019 election there are 533 constituencies in England, 40 in Wales, 59 in Scotland and 18 in Northern Ireland.

### Scotland

See also: Scottish Westminster constituencies

### Wales

See also: List of parliamentary constituencies in Wales

### Northern Ireland

See also: List of parliamentary constituencies in Northern Ireland

## Current boundary reviews

Following the abandonment of the Sixth Periodic Review (the 2018 review), the Boundary Commission for England formally launched the 2023 Review on 5 January 2021. It is due to be completed by July 2023.

## See also

* List of former United Kingdom Parliament constituencies
* Member of Parliament
* Lists of electoral districts by nation
* United Kingdom general elections overview