It has generally been accepted that electoral boundaries need to be regularly updated. Over time population levels change and so constituency boundaries must also change to reflect this. For example, there are currently 58,302 registered voters in Newcastle Upon Tyne Central and Bristol West has 99,859, but each constituency only elects one MP. 

Recent efforts to correct these kinds of imbalances have failed. However, new legislation finally paves the way for reform electoral boundaries, with the key aim of making the size of the electorate of each parliamentary constituency roughly equal.

Overview of the new boundary reviews

According to the latest framework passed by Parliament, Northern Ireland will retain its 18 parliamentary seats, rather than dropping to 17 as previously proposed. The size of the House of Commons as a will remain unchanged at 650 seats, rather than dropping to 600 as the last plan envisaged. In effect, this is a tightening up of boundaries and updating them to reflect the current electorate. 

It would be up to boundary commissions in England, Scotland, Wales and Northern Ireland to review all existing constituencies. The Northern Ireland Boundary Commission is a group of three people, independent of government and political parties. One member is a High Court judge appointed by the Lord Chief Justice of Northern Ireland, while the other two have been appointed by the Secretary of State for Northern Ireland through a public appointments process. 

Of the two appointed by the Secretary of State, one was involved in the redrawing of local council boundaries in Northern Ireland while the other previously served on several public pay commissions. This group will be responsible only for drawing up the Northern Ireland boundaries. Crucially, Parliament will not get a chance to reject them. The final recommendations of the Commission will automatically become the new boundaries in 2023. The commission will use 2020 electorate to determine the size of constituencies based on registered voters.

On this basis, the electoral quota for each constituency will be 73,392, with a 5% deviation allowed either side of this. Due to Northern Ireland’s low number of seats and geographical factors, the Northern Ireland Boundary Commission is allowed some extra leeway on these numbers.

What does the review mean for Northern Ireland?

Given that Northern Ireland will retain all 18 seats the changes are not likely to be as dramatic as those proposed in 2018 which caused much controversy and led to a court challenge.

The most significant changes will involve the movement of wards into different constituencies, along with the possibility of some constituencies being renamed. 

Under the new legislation Northern Ireland’s constituencies must fall into the range of  68,313 to 77,062 registered voters. Currently the smallest constituency is East Antrim, with 64,830 voters, while the largest is Upper Bann, with 82,887 registered voters. 

The tool available on this Boundary Assistant website is useful to seeing how exactly boundaries may change to bring these constituencies into line with the new quota. The below image shows one possible mock-up for East Antrim (with further knock-on effects in neighbouring constituencies): 

In this illustration, the East Antrim wards are shown in teal, North Antrim in grey, South Antrim in light green, and North Belfast in red. The heavy green lines show the current constituency boundaries, while the thin black lines show ward boundaries. It is important to note that the individual wards have also been updated. 

Here we see how wards such as Ballyclare East and West, along with Ballynure, could move into East Antrim from South Antrim. The North Belfast wards of Monkstown and Abbey may also move, while other boundary shifts reflect some changes to existing wards. 

A similar mock-up is presented for Upper Bann, again coloured in teal below:

Upper Bann may face more radical changes and may end up looking very different to this version. It already borders six constituencies: Newry and Armagh (yellow), Fermanagh and South Tyrone (purple), Mid Ulster (orange), South Antrim (green), Lagan Valley (blue) and South Down (pink). In this version Upper Bann. In this configuration, Upper Bann could lose Donaghcloney and Magheralin to Lagan Valley, Loughbrickland to Newry and Armagh and part of Banbridge. It also gains due to ward changes in the west of the constituency. 

These illustrations demonstrate just some possibilities, and highlight the complexity of the review process. It’s worth looking at the views of Nicholas Whyte, a leading local authority on elections in Northern Ireland. And, of course, you can use the Boundary Assistant yourself to explore different scenarios.

How are any changes likely to be received?

The final proposals are not due until 2023. Since Parliament does not get to vote on them, the Commissions’ final recommendations will become the new boundaries. Given the tight criteria on electorate sizes, and the fact Northern Ireland is not losing any constituencies, it is unlikely that may changes will be too controversial. 

It is also unlikely that the parliamentary arithmetic would change based on these changes. The DUP has the potential to become stronger in North Down while Alliance may become stronger in East Belfast. 

Ultimately, it is too soon to say whether or not the local parties will be satisfied, but we can at least expect this review to be much less controversial than the previous one. It faced considerable opposition, particularly from the DUP and SDLP. The most striking proposal was to cut Belfast’s number of seats from four to three, while there were significant changes in almost every other constituency. After further review, the Commission reversed its decision and was convinced by feedback to stick with four Belfast seats. 

The next general election is scheduled to take place in 2024 and would use the new boundaries. However, Parliament could of course vote for an earlier election. On the other hand, next Assembly election must be held before 2022, and so the existing constituency boundaries will still be in effect for at least one more contest.