The 2023 Periodic Review of Westminster constituencies was the most recent cycle of the process to redraw the constituency map for the House of Commons. The process for periodic reviews of parliamentary constituencies in the United Kingdom is governed by the Parliamentary Constituencies Act 1986, as amended by the Parliamentary Voting System and Constituencies Act 2011 and subsequently by the Parliamentary Constituencies Act 2020. This review was the successor to the 2018 Periodic Review of Westminster constituencies, which was ultimately abandoned after it failed to pass into law. Considering the abandonment of the previous reviews since 2015, the 2023 Periodic Review of Westminster constituencies is set to be the first successful review based on electoral registers drawn up using the Individual Electoral Registration model introduced from 2014-15, which has drawn criticism regarding being a measure to influence future boundary reviews in the Conservatives favour .
Under current legislation, the four Boundary Commissions of the United Kingdom were required to report on their next review of the boundaries of parliamentary constituencies before 1 July 2023. In order to meet this deadline, the Commissions began their work on 5 January 2021. Following three rounds of public consultation, all four Commissions submitted their final proposals to the Speaker of the House of Commons on 27 June 2023. The Speaker immediately laid these before Parliament and the reports were published on the respective Commissions' websites the following day.
Previous reviews
The 2013 Periodic Review of Westminster constituencies was launched by the Parliamentary Voting System and Constituencies Act 2011. The process began in 2011 and was intended to be completed by 2013, but a January 2013 vote in the House of Commons temporarily stopped the process. The 2018 Periodic Review of Westminster constituencies commenced following the 2015 general election and the four Boundary Commissions submitted their final recommendations to the Secretary of State on 5 September 2018 and made their reports public a week later. Leader of the House of Commons Andrea Leadsom told the House on 13 September 2018 that "it will be some time" before the necessary statutory instruments would be put forward for approval by both the Commons and the Lords. The proposals were never put forward for approval before the calling of the general election held on 12 December 2019, and in December 2020 the reviews were formally abandoned under the Schedule to the Parliamentary Constituencies Act 2020.
Proposed changes
The Government's policy position regarding the process for the 2023 review was confirmed in a written statement, entitled Strengthening Democracy, by Minister of State for the Cabinet Office Chloe Smith on 24 March 2020. Smith confirmed in her written statement that primary legislation would be brought forward to remove the legal requirement to give effect to the recommendations of the Sixth Review and set the framework for future boundary reviews.
The main proposals in the statement were as follows:
Maintaining 650 seats
Under the legislation which governed the unimplemented 2018 Boundary Review recommendations, the number of constituencies was to be reduced from 650 to 600. It was proposed that this be retained at 650, on the grounds that Parliament had a greater workload following the UK's departure from the European Union. Electoral quota tolerance It was proposed to maintain the current tolerance of ±5% from the average size of constituencies (the "electoral quota"). Protected constituencies It was initially proposed that there would be no change to the four protected constituencies of Isle of Wight (divided into two seats), Na h-Eileanan an Iar (the Western Isles of Scotland) and Orkney and Shetland (the Northern Isles of Scotland), which are protected from the electoral quota due to their unique geography. However, during the passage of the legislation, an amendment was introduced to add Ynys Môn (the Isle of Anglesey in Wales), increasing the number of protected constituencies to five. Boundary review cycle It was proposed that reviews be carried out every eight years, rather than the pre-2020 requirement of five years. Implementation of recommendations Under the law as it existed prior to 2020, the final proposals of the Boundary Commissions were brought into effect through an Order in Council that had to be approved by Parliament. It was proposed that the Order in Council should no longer require parliamentary approval.