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2023 constituency boundary changes

What is happening to constituency boundaries, and why? How are they changing? How are MPs affected?

Fields and houses in Ashford, England
Aerial photo of Ashford, where Damian Green MP's constituency will be split into two.

What is happening to constituency boundaries, and why?

New boundaries for parliamentary constituencies were produced as part of the 2023 boundary review process. These are intended to reflect population changes since the last constituency changes in 2010. Boundary reviews were held in both 2013 and 2018, but no changes were made due to political opposition. Boundary reviews now take place every eight years – the next review will therefore take place in 2031. 31 https://www.highpeak.gov.uk/article/2236/2023-Boundary-review

The boundary review was conducted separately by the four boundary commissions of England, Scotland, Wales and Northern Ireland. The commissions all reported to the Speaker of the House of Commons on 27 June 2023, ahead of the statutory deadline on the 1 July. The government submitted these recommendations to the Privy Council, which approved them on 15 November 2023. The new boundaries will now take effect at the next general election.

The review does not affect the boundaries of seats in the Scottish Parliament or the Welsh Senedd, which are subject to separate reviews. Seats in the Northern Ireland Assembly, however, are based on parliamentary constituencies and so will change at the next Assembly elections.

How are constituency boundaries changing?

The number of seats in the House of Commons will remain the same, after previous plans to reduce the number of seats from 650 to 600 were abandoned in 2020. 32 Proctor, K. ‘MPs no longer to get automatic vote on constituency plans’, The Guardian, 26 March 2020, retrieved 7 June 2023, www.theguardian.com/politics/2020/mar/26/mps-no-longer-to-get-automatic-vote-on-constituency-boundary-plans  England will gain 10 seats, Scotland will lose two, Wales will lose eight, and the number of Northern Irish seats will remain the same. 33 PA Media, ‘Scotland to lose two Commons seats in latest Boundary Commission proposals’, The Guardian, 8 November 2022, retrieved 7 June 2023, www.theguardian.com/uk-news/2022/nov/08/scotland-to-lose-two-commons-seats-in-latest-boundary-commission-proposals

Within England, the number of seats in the East Midlands, the East of England, London, the South East, and the South West will increase, while the number of seats in the North East, North West, and West Midlands will decrease, and the number of seats in Yorkshire and the Humber will stay the same. These changes reflect the population as measured by the electoral register in March 2020.

The scale of the change is large: of 533 existing constituencies in England, only 55 will be unchanged. 34 //boundarycommissionforengland.independent.gov.uk/wp-content/uploads/2023/06/441089_2023-06-27-Final-recommendations-key-facts-document.pdf

To take one example, the current Hackney North and Stoke Newington constituency will be split into three successor constituencies: Hackney North and Stoke Newington; Hackney South and Shoreditch; and Tottenham. The majority of people in the current Hackney North and Stoke Newington constituency will be in the new successor constituency of the same name.

What are the rules about constituency size?

The Parliamentary Constituencies Act 2020 requires that most seats have between 69,724 and 77,062 voters.

Five ‘protected’ constituencies are exempt from this rule. These are: two seats on the Isle of Wight in England; Na h-Eileanan an Iar (the Western Isles) and Orkney and Shetland in Scotland; and Ynys Môn (Anglesey) in Wales. Three of these ‘protected’ constituencies are unchanged from previous boundary reviews, while the single ‘protected’ Isle of Wight constituency which currently exists is being split into two.

No account is taken of the number of non-voters in a seat, meaning that the total population of the new seats can vary significantly. The least populated non-protected seat is New Forest West (population: 85,000), while the most populated is Birmingham Ladywood (population: 152,000). 38 //commonslibrary.parliament.uk/constituency-boundary-review-data-for-new-constituencies/

How are MPs affected?

The changes will not take effect until the next general election, meaning that current MPs are unaffected. However, those whose seats are changing significantly – or even being abolished – may have to choose whether to attempt to gain selection as a candidate in a different seat or to stand down from parliament at the next election.

Occasionally, sitting MPs from the same party may compete to be selected for the same new seat. Labour MP Alison McGovern, whose Wirral South seat is due to be abolished, competed with sitting Labour MP Mick Whitley for selection in Whitley’s Birkenhead constituency. McGovern was selected by the constituency Labour party, displacing Whitley. 39 //labourlist.org/2023/06/alison-mcgovern-selection-birkenhead-mick-whitley-wirral/  Conservative MPs in seats considered ‘at risk’ under the new boundaries can be declared ‘displaced’ by Conservative Campaign Headquarters, making them eligible for selection in other, safer seats. 40 Allegretti, A., ‘Tory MPs at risk of losing seats allowed to stand in other constituencies’, The Guardian, 14 April 2023, www.theguardian.com/politics/2023/apr/14/tory-mps-at-risk-losing-seats-allowed-stand-other-constituencies-next-election

The table below shows exactly which constituencies will be affected most, by comparing current constituencies and their closest successor constituencies. The percentages shown are the percentage of population in common between current and successor constituencies, as calculated by the House of Commons Library.

Who made these changes?

The boundary reviews were conducted in each nation by the boundary commissions for England, Scotland, Wales and Northern Ireland.

The 2023 review began with the Parliamentary Constituencies Act 2020. In England, the boundary commission’s initial proposals were published in 2021, followed by revised proposals in 2022. Three rounds of public consultation were held, the last of which closed in December 2022. More than 60,000 public responses were received. 47 //boundarycommissionforengland.independent.gov.uk/wp-content/uploads/2023/06/2023-06-28-BCE-final-recommendations-press-release.pdf

Can the government influence the proposals?

No. The four boundary commissions are independent and non-partisan arms-length bodies. The Boundary Commission for England is sponsored by the Department for Levelling Up, Housing and Communities, while the Scottish, Welsh and Northern Irish commissions are sponsored by their respective territorial offices.

All of the boundary commissions are chaired by the Speaker of the Commons – though he is not able to influence their recommendations – and are composed of a High Court judge and two publicly-appointed commissioners. The sponsoring government departments provide funding, staff and resources for the commissions. 48 //boundarycommissionforengland.independent.gov.uk/about-us/

Does the government have to accept the proposals?

The government is not permitted to modify the recommendations unless requested to do so by one of the commissions. Under the Parliamentary Constituencies Act 2023, the government was obliged to submit the recommendations to the Privy Council as a draft Order in Council within four months of the proposals being received. 49 //boundarycommissionforengland.independent.gov.uk/wp-content/uploads/2021/05/2021-04-20-Guide-to-the-2023-Review.pdf  The Privy Council approved this draft Order on 15 November 2023.

Implementing the boundary changes without a vote in parliament avoids the possibility that MPs will block the reforms, as has happened in the past. In 2013, the Liberal Democrats voted with Labour to block the coalition government’s boundary reforms in retaliation for the Conservatives’ failure to support the party’s House of Lords reforms. In 2020, the government announced that MPs would not be given a vote on future boundary reforms. 50 Proctor, K. ‘MPs no longer to get automatic vote on constituency plans’, The Guardian, 26 March 2020, retrieved 7 June 2023, www.theguardian.com/politics/2020/mar/26/mps-no-longer-to-get-automatic-vote-on-constituency-boundary-plans  Instead, reviews will occur automatically every eight years (rather than every five years, as previously occurred).

When have boundaries been changed before?

Constituency boundaries last changed at the 2010 general election. Regular reviews of parliamentary constituencies have been held since the House of Commons (Redistribution of Seats) Act 1944. 51 //researchbriefings.files.parliament.uk/documents/SN05929/SN05929.pdf

Previous boundary reviews were held in 2013 and 2018, following the passage of the 2011 Parliamentary Voting System and Constituencies Act. If implemented, these reviews would have reduced the number of seats in parliament from 650 to 600. However, neither review was implemented. The 2013 reforms were blocked by MPs and the 2018 boundary review was scrapped in 2020 after the government argued that Brexit would increase MPs’ workloads. 52 Proctor, K. ‘MPs no longer to get automatic vote on constituency plans’, The Guardian, 26 March 2020, retrieved 7 June 2023, www.theguardian.com/politics/2020/mar/26/mps-no-longer-to-get-automatic-vote-on-constituency-boundary-plans

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