The new Northern Ireland constituencies

Since 2007 I’ve been the Northern Ireland arm of the analysis of UK parliamentary constituency changes by Michael Thrasher and Colin Rallings. The latest version, taking into account the new boundaries that will take effect from the next election (be it Westminster or Assembly) was published a few weeks ago; it’s been a busy period for me, but I have now taken the time to write up the changes to each of the 18 Northern Ireland seats.

Media coverage coverage of the changes focussed on the effects in England, Scotland and Wales, and frankly that was the right call; the changes in Northern Ireland are the least dramatic since the 1970s. The 1983 review added five new constituencies, taking the total from 12 to 17; the 1996 review added another, making a total of 18; and the 2007 review expanded the Belfast seats outwards with knock-on effects all around the map.

There were also two failed reviews, one in 2013 which fell victim to the internal politics of the Conservative-Lib Dem coalition, and one in 2018-20 which was quashed by the Belfast courts for failing to adequately consider public opinion at the final stage of revision (and the whole thing was then killed off by Boris Johnson).

So this is the first change to the Westminster constituencies for 17 years, the longest gap since the 1950-70 period. In Northern Ireland the Westminster boundaries are also used for Assembly elections, and indeed in 1973 and 1996, regional level elections used the new boundaries first. Personally I think that the Assembly constituencies should be linked to the Local Government Districts rather than the Westminster seats, but that’s for another day.

Every seat is changed this time, but few of the changes are drastic. In the list below, I’m going from the most changed to the least changes constituency, showing my working for each of them. Notional votes are a bit of a mug’s game, but I’m confident that these numbers correspond closely to whatever the reality might have been if the 2019 general election votes had been cast on the 2024 boundaries.

The maps are all screenshotted from the Guardian’s excellent site, which you should consult.

South Belfast and Mid Down (SBMD)

Going from most to least changed, the biggest effect is on the constituency where I grew up, South Belfast, now renamed to South Belfast and Mid Down. It loses 10% of its electorate to East Belfast, but gains a bit more than that from Strangford and Lagan Valley, and a few scrapings from West Belfast. (By the way, I have an idiosyncracy of calling the Belfast constituencies “X Belfast” rather than “Belfast X”. It seems to me that “South Belfast and Mid Down” sounds better than “Belfast South and Mid Down.)

Projecting the 2019 election onto the new boundaries, I see about 850 more Unionist votes, 550 more for Alliance and 1650 fewer for the SDLP, with another 250 Nationalist votes coming in from West Belfast. Claire Hanna won the seat with a majority of over 15,000 in 2019; this would be reduced by 2,000, but the SDLP still win more than half of the votes in the constituency.

RollDUPUUPConAPNIGrPBPSDLPSFAontu
70134 116781259678627079550
FromTo24.7%2.7%14.3%57.2%1.2%
SBSBMD63029 97861055602825136550
SBEB-7096 -1890-204-758-1939
SBWB-9 -1-3-1
StrSBMD 6078 163437213698173207
LVSBMD 2161 611276313203422
WBSBMD 710 5620673222518
Total71978 1208717031677348736725409247568
25.4%3.6%0.3%15.4%0.2%0.1%53.3%0.5%1.2%
Change+0.7%+0.9%+0.3%+1.1%+0.2%+0.1%-3.9%+0.5%
DUPUUPConAPNIGrPBPSDLPSFAontu

Sinn Fein did not contest the 2019 Westminster election, but they could take almost half of the SDLP vote and Claire Hanna would still win the seat. She bantered with me on social media about looking forward to the challenge.

https://twitter.com/ClaireHanna/status/1747571230847176753

At Assembly level, Unionists combined were just short of 2 quotas in South Belfast in 2022, and these numbers would put them just about in position to regain the second seat lost in 2017.

Strangford

Neighbouring Strangford loses 6,000 voters, mainly in Saintfield, to the new Belfast South and Mid Down, but gains 9,000 around Downpatrick from South Down.

This results in the biggest shift in party support in any constituency.

RollDUPUUPUKIPConsAPNIGrSDLPSFAontu
66990 1770540233081476106347901994555
FromTo47.2%10.7%0.8%3.9%28.4%2.1%5.3%1.5%0.0%
StrStr60899 160683651308134096517171787555
StrSBMD-6078 -1634-372-136-981-73-207
StrND-10 -3-1-2
StrS-3 -1
SDStr 9171 602680022152462193
Total16128367730813401045171740023017193
40.5%9.2%0.8%3.4%26.2%1.8%10.0%7.6%0.5%
-6.7%-1.5%0.0%-0.6%-2.1%-0.3%+4.7%+6.1%+0.5%
DUPUUPUKIPConsAPNIGrSDLPSFAontu

The DUP majority over Alliance here is reduced from 7,000 to 5,700, and if you squint you could just about see a unified non-Unionist candidate defeating a split opposition at a Westminster election; but it’s not very likely. From the Assembly point of view, the Nationalist vote increases by more than 10% and is now over a quota. At every Assembly election since 1998, the SDLP have been runners-up here; whichever of the Nationalist parties can get ahead of the other now has a good chance of gaining a seat here.

South Down

Staying in the neighbourhood, the calculations for South Down were much the most complex. It swaps bits of territory with three of its neighbours, most notably donating the voters around Downpatrick to Strangford, and also makes a gain from Upper Bann (my ancient homeland of Loughbrickland).

Although the shifts are geographically complex, the electoral impact is muted.

RollDUPUUPConsAllianceSDLPSFAontu
79295 76193307691614517161371266
FromTo15.3%6.6%0.0%13.9%29.2%32.4%2.5%
SDSD6864674173219598712032133741049
SDStr-9171-60-26-800-2215-2462-193
SDN&A-1458-140-61-127-267-297-23
SDLV-20-2-1-2-44
UBSD 1960 57417415283221
N&ASD 1058 143555512326421
LVSD 105 271211822
StrSD 3 1
Total 71,772 816234601621212240138611070
18.1%7.7%13.8%27.2%30.8%2.4%
+2.8%+1.0%-0.1%-2.0%-1.6%-0.2%
DUPUUPConsAPNISDLPSFAontu

SF won this seat with a 1300 majority in 2019, and I don’t see much change to that in my notional result. The overall Nationalist vote share decreases by 3.8% and the overall Unionist share increases by the same amount. This is still not enough to put Unionists in play for a second Assembly seat.

Lagan Valley

Rounding off the middle of County Down, Lagan Valley loses Drumbo to South Belfast and Mid Down, and more significantly Dunmurry to West Belfast, while gaining the eastern fringes of Lurgan from Upper Bann.

Again, it looks bigger on the map than it actually is.

RollDUPUUPUKIPConsAPNISDLPSF
75884 1958686063159551308717581098
FromTo 43.1%19.0%0.7%2.1%28.8%3.9%2.4%
LVLV 68948 180207910315878117931441900
LVWB-4330 -840-3700-41-898-272-170
LVSBMD-2161 -611-2760-31-320-34-22
LVSA-340 -88-390-4-59-8-5
LVSD-105 -27-120-1-18-2-2
UBLV 7364 1818550005714101090
SDLV 20 2100244
Total 76,332 1984084603158781236518551994
43.4%18.5%0.7%1.9%27.1%4.1%4.4%
+0.3%-0.4%+0.0%-0.2%-1.8%+0.2%+1.9%

The DUP’s 6,500 majority over Alliance in 2019 increase to 7,500 (what you might call the Dunmurry effect), and the total non-Unionist vote upticks very slightly. At Assembly level, Nationalists were able to win a seat in Lagan Valley in a good year, and these changes make good years more likely, though Alliance would still have a good chance of holding their second seat.

West Belfast

Looking north of Lagan Valley, West Belfast loses a few nibbles around the edges but gains 9,000 voters from Dunmurry at one end and the Shankill at the other.

Neither of the newly added patches of territory is great for SF, but they are pretty far ahead anyway.

RollDUPUUPConsAPNIPBPSDLPSFAontu
65761 5220188261942985208661635
FromTo13.5%4.9%16.0%7.7%53.8%4.2%
WBWB62538 4084181360582919204081599
WBNB-2393-1071-45-57-28-195-16
WBSBMD-710-56-20-67-32-225-18
WBSA-120-10-3-11-5-38-3
NBWB5044 2,863 348 208
LVWB4330 840 370 41 898 272 170
SBWB9 1 1 3 0
Total71921778937041306060583195207861599
18.2%0.9%0.1%7.1%14.1%7.4%48.5%3.7%
+4.7%+0.9%+0.1%+2.3%-1.8%-0.2%-5.3%-0.5%
DUPUUPConsAlliancePBPSDLPSFAontu

This is the second biggest shift of party support in any constituency, but I don’t think SF will be awfully troubled by the prospect of their 14000 majority over PBP at Westminster being reduced to a 12000 majority over the DUP; the seat is safe as houses anyway. Unionist candidates were runners-up here in every assembly election since 1998, with the exception of 2003 when Diane Dodds actually won. There is now a clear prospect of a safe(ish) Unionist seat at the next Assembly election.

Upper Bann

As noted already, Upper Bann loses Loughbrickland to South Down and its eastern fringes to Lagan Valley, but gains parts of the apple country of North Armagh. It was the most bloated constituency on the old boundaries.

The result looks big on the map but has little net electoral impact.

RollDUPUUPAllianceSDLPSFAontu
830282050161976433462312291
FromTo41.0%12.4%12.9%9.2%24.6%
UBUB737041810954745711413010980
UBLV-7364-1818-550-571-410-1090
UBSD-1960-574-174-152-83-221
N&AUB326582231416922147438
Total76969189315788588043511145438
40.8%12.5%12.7%9.4%24.7%0.1%
-0.2%0.1%-0.2%0.1%0.1%0.1%
DUPUUPAllianceSDLPSFAontu

The DUP majority at Westminster drops from just over 8000 to just under 8000. The last Assembly seat here in 2022 was won by Alliance with a 376 vote margin over SF; that would look vulnerable under these changes.

East Belfast

This is very straightforward, with a loss to North Down in one direction and gains from South Belfast in the other.

This does bring in notional South Belfast SDLP votes (the SDLP did not stand in East belfast in 2019).

RollDUPUUPAllianceSDLP
66273 20874251619055
FromTo49.2%5.9%44.9%0.0%
EBEB62980 19726237818232
EBND-3293-1148-138-823
SBEB 7096 18902047581939
Total 70076 216162581189901939
47.9%5.7%42.1%4.3%
-1.3%-0.2%-2.8%4.3%
DUPUUPAllianceSDLP

The DUP’s majority in 2019 was 1800, and the changes expand that to 2600. But those 1939 notional SDLP votes could go a long way to making up the difference in one of the tightest results. I don’t see any direct impact on Assembly representation; there is still nowhere near a Nationalist quota.

North Belfast

Jumping across the river now, we have some tinkering around the margins of North Belfast; the biggest changes are the smallest on the map, to West Belfast on the Shakill and to and from South and East Antrim in Newtownabbey,

These changes basically don’t help the DUP to regain the seat lost in 2019.

DUPUUPConsAlliancePBPSDLPSFAontu
21135482423078
FromTo7233243.1%9.8%47.1%
NBNB6671118103443722686
NBWB-5044-2863-348-208
NBSA-577-169-38-184
WBNB2393107145572819516
SANB19261571325631922670
EANB34289295545110
Total713721941916155099572252315816
40.3%0.3%0.0%10.6%0.1%0.5%48.1%0.0%
-2.8%0.3%0.0%0.8%0.1%0.5%1.0%0.0%
DUPUUPConsAlliancePBPSDLPSFAontu

SF’s 1900 majority in 2019 expands to 3700. And it’s difficult to see any change in Assembly representation either.

East Antrim

Continuing up the coast, we reach East Antrim which swaps large but sparsely populated territory with North Antrim.

It doesn’t make a lot of difference to the results though.

RollDUPUUPConsAllianceGreenSDLPSF
64907 1687154751043101656859022120
FromTo45.3%14.7%2.8%27.3%1.8%2.4%5.7%
EAEA 62640 162825284100798106858702046
EANA-1045-272-88-17-1640-15-34
EASA-880-229-74-14-1380-12-29
EANB-342-89-29-5-540-5-11
NAEA70364821342058305531057
SAEA26055450300818
Total6993616818667110071042368514323120
41.9%16.6%2.5%26.0%1.7%3.6%7.8%
-3.4%+1.9%-0.3%-1.3%-0.1%+1.1%+2.1%

The DUP’s actual majority of 6700 over Alliance is reduced to a notional 6400, which won’t cause sleepless nights. There are clearly two non-Unionist quotas for the Assembly, and equally clearly Nationalists will struggle to get one of them.

Newry and Armagh

Back to the south of Northern Ireland again, where Newry and Armagh, the second most bloated seat under the old boundaries, loses most of the apple country to Upper Bann and Fermanagh-South Tyrone, and tidies up its eastern boundary.

The territory lost is at the more Unionist end of the constituency.

DUPUUPAllianceSDLPSFAontu
11000420442119449202871628
FromTo 81329 21.7%8.3%8.3%18.6%40.0%3.2%
N&AN&A 73,127 9275354537868753187921508
N&AFST-3879-760-290-201-353-757-61
N&AUB-3265-822-314-169-221-474-38
N&ASD-1058-143-55-55-123-264-21
SDN&A 1458 1406112726729723
Total 74585 9415360539139019190881531
20.2%7.7%8.4%19.4%41.0%3.3%
-1.4%-0.5%0.1%0.8%1.0%0.1%

SF’s 2019 majority increases from almost 9300 to over 9600. For the Assembly, a second Unionist seat slips a little further away.

North Antrim

Back up to the north again as North Antrim swaps territory with East Antrim and comes out a bit smaller.

Changes that look big on the map don’t always have much effect on the ground.

DUPUUPConsAllianceIndSDLPSF
77156 208608139623124629435632
47.4%18.5%0.0%14.1%0.6%6.7%12.8%
NANA70120 203786797564824623904575
NAEA7036 -482-1342-583-553-1057
EANA104527288171641534
Total71165 20650688517581124624044609
50.8%16.9%0.0%14.3%0.6%5.9%11.3%
3.5%-1.5%0.0%0.2%0.0%-0.8%-1.4%
DUPUUPConsAllianceIndSDLPSF

I see the DUP’s notional majority here increasing slightly from 12,000 to 13,000. From three quotas they should notionally get three Assembly seats, but Jim Allister was not a candidate in 2019.

Fermanagah and South Tyrone

Out West now, where the maths is fairly simple but the politics complicated. Fermanagh and South Tyrone was pretty close to the required size, but because of other changes must gain some net territory from Newry and Armagh, and lose a bit to Mid Ulster.

On paper, the differences are not huge.

RollDUPUUPAllianceIndSDLPSFAontu
72945219292650751344621986
0.0%43.2%5.2%1.5%6.8%43.3%0.0%
FSTFST69887227222761751360823017
FSTMU-3058-793-111-162-1031
N&AFST387976029020135375761
MUFST877136324479255
Total7464389621458278475137172196861
1.7%41.6%5.4%1.5%7.2%42.5%0.1%
1.7%-1.6%0.2%0.0%0.4%-0.8%0.1%
DUPUUPAllianceIndSDLPSFAontu

But this was the tightest result in Northern Ireland in 2019, SF beating the UUP by a mere 57 votes. The notional majority is now 510; but there are 896 notional DUP votes in the mix. So Northern Ireland’s closest race may actually have got a bit closer.

Mid Ulster

This was one boundary change that I called completely incorrectly. I had expected that Mid Ulster would stretch north towards Dungiven, as had been the case in the previous quashed proposals. But in fact it takes a chunk of Coalisland from Femanagh and South Tyrone, which losing a large but sparsely populated chunk to West Tyrone.

It doesn’t make a lot of difference.

RollDUPUUPAllianceIndSDLPSF
70501 1093626113526690638420473
24.5%5.9%7.9%1.5%14.3%45.9%
MUMU67036 1056625233284690603119342
MUWT-2588 -234-56-198-273877
MUFST-877 -136-32-44-79255
FSTMU30587931111621031
Total700941056633163395690619320372
23.7%7.4%7.6%1.5%13.9%45.7%
-0.8%1.6%-0.3%0.0%-0.4%-0.1%
DUPUUPAllianceIndSDLPSF

SF’s 9,500 majority extends to a notional 9,800, and the needle is not really moved for the Assembly seats.

Foyle

A little trimming at the edges to East Londonderry and West Tyrone.

The changes are minor, and although more Nationalist than Unionist voters are moved, the Unionist vote share is hit worse.

RollDUPUUPAlliancePBPSDLPSFAontu
7443147731088126713322688197712032
FromTo10.1%2.3%2.7%2.8%57.0%20.7%4.3%
FoyleFoyle698903852878118912512578593721949
FoyleELy-2854-691-157-49-51-591-215-45
FoyleWT-1687-230-53-29-30-505-184-38
69890 3,852 878 1,189 1251 25785 9372 1,949
8.7%2.0%2.7%2.8%58.2%21.2%4.4%
-1.4%-0.3%0.0%0.0%1.2%0.4%0.1%
DUPUUPAlliancePBPSDLPSFAontu

The SDLP’s 17,100 majority in 2019 is reduced to a mere 16,400 which I don’t think will trouble them unduly. The DUP won the last Assembly seat here by a margin of 95 votes over the UUP, the closest result of the 2022 election, and on the above swing it would be vulnerable, but the picture is very much blurred by tactical voting.

West Tyrone

Simply takes in adjacent chuncks from Mid Ulster and Foyle.

These are small territories, sparsely populated, and don’t make a lot of difference.

RollDUPUUPAllianceGreenPBPSDLPSFAontu
66339 9066277439795210733016544972
22.0%6.7%9.7%1.3%0.0%17.8%40.2%2.4%
WTWT66339 9066277439795210733016544972
MUWT2588 23456198002738770
FoyWT1687 230532903050518438
Total70614 953028824206521308108176041010
21.7%6.6%9.6%1.2%0.1%18.5%40.1%2.3%
-0.3%-0.2%-0.1%-0.1%+0.1%+0.7%-0.1%-0.1%
DUPUUPAllianceGreenPBPSDLPSFAontu

The SF notional majority increases from almost 7500 to almost 8100. No impact on the Assembly result.

South Antrim

Getting near the end now, with South Antrim by far the most annoying to calculate: lots of little changes that don’t add up to anything much, the biggest being chunks of Glengormley going to North Belfast.

A real pain to work out these very small notionals!

RollDUPUUPConsAlliancePBPSDLPSFAontu
71915 1514912460819022884887
35.3%29.0%19.1%5.3%11.4%
SASA69729 1493712283759720884603
SANB1926 -157-132-563-192-267
SAEA260 -55-45-30-8-18
EASA88022974141381229
NBSA57716938184
LVSA340883945985
WBSA120103115383
Total71646154321239618783611211348583
36.2%29.1%0.0%18.4%0.0%5.0%11.4%0.0%
+0.9%+0.1%-0.7%-0.4%
DUPUUPConsAlliancePBPSDLPSFAontu

In a good year, the UUP could overtake the DUP here, and in a much much better year the same is true for Alliance. But the boundary changes have little impact on the Westminster or Assembly outcomes.

North Down

Takes in a small sliver of Strangford and a larger sliver of East Belfast.

The Alliance Party’s strongest seat takes in 3000 voters from the Alliance Party’s second strongest seat.

DUPUUPConsAlliance
153904936195918358
67,109 37.9%12.1%4.8%45.2%
NDND 67,109 153904936195918358
EBND 3,293 11481380823
StrND 10 3102
Total 70,412 165415075195919182
38.7%11.9%4.6%44.9%
0.8%-0.3%-0.2%-0.3%
DUPUUPConsAlliance

Alliance’s Westminster majority is reduced from almost 3000 to just over 2600, so the seat remains competitive but they are starting ahead. The shifts are so small that it’s difficult to see much impact on the Assembly.

East Londonderry

Gains a ward from Foyle.

Small numbers make for small differences.

DUPUUPAlliancePBPSDLPSFAontu
693591576535995921615861281731
40.1%9.2%15.1%15.7%15.6%4.4%
ELyELy693591576535995921615861281731
FoyELy2854691157495159121545
Total72213164563756597051674963431776
40.0%9.1%14.5%0.1%16.4%15.4%4.3%
-0.1%-0.5%+0.1%+0.8%-0.2%-0.1%
DUPUUPAlliancePBPSDLPSFAontu

The DUP’s Westminster majority is unchanged. It’s difficult to see much impact on the Assembly election, especially if independent MLA Claire Sugden remains active.

So there you have it. A Westminster election is likely before the end of the year. It may well see some changes of seats, but the new boundaries are unlikely to make the difference.