Wales: New Constituency Boundaries 2023

Each new seat can be described as a combination of parts of old seats. These tables show this decomposition. The winner of the old seat at the 2019 election is shown by party colour, as is the implied winner of the new seat.

The implied results are calculated using the local election results for the wards which make up each old seat. This should give the most accurate projection, since it reflects varying political behaviour across the seat.

Wales Change Table

PartyOld SeatsNew SeatsChangeDisappearSwitch OutSwitch InFresh
CON1412-2-4020
LAB2218-4-3-100
LIB0000000
Brexit0000000
Green0000000
Plaid42-2-1-100
MIN0000000
Total4032-8-8-220

The table shows how the various changes affect each party in this area. The total old and new seats are shown for each party, as well as their difference ('Change'). The change in seats is also explained through the four explanations:

The old seats which are disappearing are: Arfon; Bridgend; Carmarthen West and Pembrokeshire South; Clwyd South; Cynon Valley; Newport West; Swansea West; Vale of Clwyd.

The old seats which are lost to another party are: Alyn and Deeside; Carmarthen East and Dinefwr.

The new seats which are gained from another party are: Alyn and Deeside; Carmarthen.

Clwyd

New seatPrimary componentSecondary component(s)
Aberconwy 100% of Aberconwy 35.8% of Arfon
16.9% of Clwyd West
Alyn and Deeside 100% of Alyn and Deeside 11.3% of Delyn
9.1% of Clwyd South
Clwyd 70.2% of Clwyd West 64.1% of Vale of Clwyd
Delyn 88.7% of Delyn 35.9% of Vale of Clwyd
12.9% of Clwyd West
Wrexham 100% of Wrexham 47.8% of Clwyd South

Dyfed

New seatPrimary componentSecondary component(s)
Carmarthen 80.6% of Carmarthen East and Dinefwr 40.7% of Carmarthen West and Pembrokeshire South
Ceredigion Preseli 100% of Ceredigion 33.8% of Preseli Pembrokeshire
Llanelli 100% of Llanelli 19.4% of Carmarthen East and Dinefwr
Pembrokeshire Mid and South 66.2% of Preseli Pembrokeshire 59.3% of Carmarthen West and Pembrokeshire South

Gwent

New seatPrimary componentSecondary component(s)
Blaenau Gwent and Rhymney 100% of Blaenau Gwent 20.3% of Merthyr Tydfil and Rhymney
9.2% of Caerphilly
4.8% of Islwyn
Islwyn 95.2% of Islwyn 26.3% of Caerphilly
Monmouthshire 88.2% of Monmouth 23.0% of Newport East
Newport East 77.0% of Newport East 45.8% of Newport West
Newport West and Caerphilly 59.0% of Caerphilly 54.2% of Newport West
Torfaen 100% of Torfaen 11.8% of Monmouth

Gwynedd

New seatPrimary componentSecondary component(s)
Dwyfor Meirionnydd 100% of Dwyfor Meirionnydd 64.2% of Arfon
Ynys Mon Unchanged

Mid Glamorgan

New seatPrimary componentSecondary component(s)
Bridgend 78.2% of Ogmore 46.3% of Bridgend
Merthyr Tydfil and Aberdare 79.7% of Merthyr Tydfil and Rhymney 44.1% of Cynon Valley
5.5% of Caerphilly
0.0% of Brecon and Radnorshire
Pontypridd 70.6% of Pontypridd 55.9% of Cynon Valley
0.0% of Ogmore
Rhondda 100% of Rhondda 20.6% of Ogmore
15.8% of Pontypridd

Powys

New seatPrimary componentSecondary component(s)
Brecon and Radnor 100% of Brecon and Radnorshire 30.4% of Neath
Montgomeryshire and Glyndwr 100% of Montgomeryshire 43.1% of Clwyd South

South Glamorgan

New seatPrimary componentSecondary component(s)
Cardiff Central 100% of Cardiff Central 18.3% of Cardiff South and Penarth
0.0% of Cardiff North
Cardiff North 100% of Cardiff North 4.7% of Pontypridd
0.1% of Cardiff South and Penarth
Cardiff South and Penarth 81.6% of Cardiff South and Penarth 8.3% of Vale of Glamorgan
Cardiff West 100% of Cardiff West 8.9% of Pontypridd
1.2% of Ogmore
Vale of Glamorgan 91.7% of Vale of Glamorgan

West Glamorgan

New seatPrimary componentSecondary component(s)
Aberafan Porthcawl 83.8% of Aberavon 53.7% of Bridgend
Swansea Central and North 61.8% of Swansea East 46.5% of Swansea West
20.5% of Gower
Swansea East and Neath 69.6% of Neath 37.4% of Swansea East
16.2% of Aberavon
9.2% of Gower
Swansea West and Gower 70.4% of Gower 53.5% of Swansea West
0.8% of Swansea East