This Insight looks at how constituency boundaries will change in the UK, and provides maps to view how the current constituencies relate to new ones.
Constituency boundaries in the UK are changing. A new set of boundaries for Westminster constituencies will be used at the next UK general election.
While statistics are widely available for the current set of parliamentary constituencies, there is less data about these new constituencies. This Insight provides statistical profiles of the new constituencies from the available data and explains when more data might become available.
How are constituency boundaries changing?
The four Boundary Commissions for England, Scotland, Wales and Northern Ireland have reviewed the UK’s constituency boundaries. They published their final recommendations in June 2023, and the new boundaries they have set out will be used at the next UK general election.
The Library has published an Insight explaining which seats will change in more detail, featuring an interactive map showing individual boundary changes.
Around 10% of constituencies will have no change to their boundaries. The remainder will change in some way. In some cases, a ward or several wards will move between constituencies. In others, the changes will be more complicated, ranging from small boundary adjustments to constituencies being ‘abolished’ and split between several successor constituencies.
Get demographic data about new constituencies
The Office for National Statistics (ONS) and the Northern Ireland Statistics and Research Agency (NISRA) have released census data for the new constituency boundaries in England, Wales and Northern Ireland.
We have compiled some of this data in a file which you can download below:
The file has statistics on the following topics for England, Wales and Northern Ireland:
- Total population
- Total number of households
- Age groups
- Country of birth
- Ethnic groups
- Home ownership and renting.
Scotland’s census was delayed by a year, and the results have not yet been published. The file above instead uses population estimates for mid-2021 in Scottish Data Zones published by the National Records of Scotland. We have added this data together to approximate the new constituency boundaries.
These figures include the total population and an age breakdown, but data isn’t available for the other demographic variables.
Where else can I find data about new constituencies?
Census data for England and Wales
The ONS’ data on new constituencies is published as part of its Create a custom dataset tool.
To get data from the tool, select a population type and click ‘continue’, and then change the ‘area type’ to ‘post-2019 Westminster parliamentary constituencies’. You can then add census variables to your dataset and download a data file.
The ONS also has an online Build a custom area profile tool which has census data for new constituencies in England and Wales.
The tool lets you either draw your own geographical area or search pre-defined areas that include the new constituencies. You can then build a statistical profile based on census data.
The images below show how to use the tool. First, type the name of a new constituency into the search box, and select the version with the ‘future constituency’ caption. Then click on the ‘Build profile’ button in the top-right corner.
Image © ONS. Map © Ordnance Survey.
When building a profile, you can select the census variables that you’re interested in and add them to a profile of the constituency. You can then export your profile as an image or a data file.
Image © ONS. Map © Ordnance Survey.
Census data for Northern Ireland
NISRA has published census statistics for the new constituency boundaries as part of its Flexible table builder tool.
To get data, use the ‘Build a custom table’ link, and when choosing a geographical area select ‘Parliamentary constituency 2024’.
When will there be more data for new constituencies?
Data from official statistics producers
At time of writing, no further data for new constituency boundaries has been published by official statistics producers. Eventually, data for new constituencies will be available from the ONS and from government departments that normally provide constituency-level data, such as the Department for Work and Pensions.
In some cases, data for the new constituencies might only be produced after a general election has taken place and the new constituencies are in operation.
Data from the Commons Library
The Commons Library is publishing more data for new constituency boundaries, based on our own analysis, on the Library website. You can find everything we’ve published so far here.
We also publish a range of statistics for current constituencies and other local areas, primarily through our constituency data dashboards.
During this parliament, our focus is on providing data for the current constituencies represented by sitting MPs. Our data dashboards will therefore continue to provide data for current constituencies, and they will be updated to show new constituencies after the next general election.
We will publish these updates as soon as is practical. We plan to publish updates on some topics, including demographic data, the day after the general election.
For some other topics, we will only be able to provide data once it has been published by official statistics producers (see above).
For MPs and their offices the Library’s confidential requests service might be able to answer specific questions about new constituencies where small-area data is available, such as for transport, child poverty and broadband.
Cassie Barton: Cassie Barton is a House of Commons Library statistician specialising in demography and housing.
This Insight was amended on 28.11.2023 to explain new 2021 census data published by ONS, and on 27.09.2023 to include new constituency data published by NISRA. Both updates included changes to the data file for download.
A look at how voter weight would change in different areas if the constituency boundary review proposals go ahead.
Final consultations on proposals to change parliamentary constituency boundaries are due or underway.