Wales: New Constituency Boundaries 2018

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 2017 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

  Old SeatsNew SeatsChangeDisappearSwitch OutSwitch InFresh
Con85-3-3-110
Lab2822-6-7-120
Lib0000000
Ukip0000000
Green0000000
Nat42-2-1-100
Min0000000
Total4029-11-11-330

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: Aberavon; Aberconwy; Arfon; Cardiff Central; Carmarthen West and Pembrokeshire South; Delyn; Gower; Islwyn; Montgomeryshire; Newport East; Pontypridd.

The old seats which are lost to another party are: Carmarthen East and Dinefwr; Clwyd South; Vale of Glamorgan.

The new seats which are gained from another party are: Carmarthen; Clwyd South and Montgomeryshire North; Vale of Glamorgan East.

Clwyd

New seatPrimary componentSecondary component(s)
Alyn and Deeside 100% of Alyn and Deeside 31.5% of Delyn
Clwyd South and Montgomeryshire North 56.2% of Clwyd South 43.5% of Montgomeryshire
21.4% of Clwyd West
16.4% of Vale of Clwyd
Conwy and Colwyn 72.0% of Clwyd West 67.1% of Aberconwy
12.6% of Vale of Clwyd
Flint and Rhuddlan 71.0% of Vale of Clwyd 68.5% of Delyn
Wrexham 100% of Wrexham 43.8% of Clwyd South

Dyfed

New seatPrimary componentSecondary component(s)
Carmarthen 92.4% of Carmarthen East and Dinefwr 40.8% of Carmarthen West and Pembrokeshire South
Ceredigion and Pembrokeshire North 100% of Ceredigion 24.0% of Preseli Pembrokeshire
7.6% of Carmarthen East and Dinefwr
8.4% of Montgomeryshire
Llanelli 100% of Llanelli 32.0% of Gower
Pembrokeshire South and Mid 76.0% of Preseli Pembrokeshire 59.2% of Carmarthen West and Pembrokeshire South

Gwent

New seatPrimary componentSecondary component(s)
Blaenau Gwent 100% of Blaenau Gwent 48.8% of Islwyn
Caerphilly 63.9% of Caerphilly 46.5% of Islwyn
20.7% of Newport West
Monmouthshire 87.9% of Monmouth 35.9% of Newport East
Newport 68.9% of Newport West 64.1% of Newport East
Torfaen 100% of Torfaen 12.1% of Monmouth
10.3% of Newport West

Gwynedd

New seatPrimary componentSecondary component(s)
Anglesey and Bangor 100% of Ynys Mon 42.5% of Arfon
13.8% of Aberconwy
Gwynedd 100% of Dwyfor Meirionnydd 57.5% of Arfon
19.2% of Aberconwy
6.6% of Clwyd West

Mid Glamorgan

New seatPrimary componentSecondary component(s)
Bridgend and Vale of Glamorgan West 100% of Bridgend 20.2% of Vale of Glamorgan
2.0% of Ogmore
Cynon Valley and Pontypridd 100% of Cynon Valley 50.0% of Pontypridd
Merthyr Tydfil and Rhymney 100% of Merthyr Tydfil and Rhymney 36.1% of Caerphilly
4.7% of Islwyn
Ogmore and Aberavon 92.5% of Ogmore 58.8% of Aberavon
Rhondda and Llantrisant 100% of Rhondda 45.1% of Pontypridd
5.4% of Ogmore

Powys

New seatPrimary componentSecondary component(s)
Brecon, Radnor and Montgomery 100% of Brecon and Radnorshire 48.2% of Montgomeryshire

South Glamorgan

New seatPrimary componentSecondary component(s)
Cardiff North 93.6% of Cardiff North 37.6% of Cardiff Central
Cardiff South and East 54.3% of Cardiff South and Penarth 62.4% of Cardiff Central
6.4% of Cardiff North
Cardiff West 100% of Cardiff West 16.1% of Cardiff South and Penarth
4.8% of Pontypridd
Vale of Glamorgan East 79.8% of Vale of Glamorgan 29.6% of Cardiff South and Penarth

West Glamorgan

New seatPrimary componentSecondary component(s)
Gower and Swansea West 83.1% of Swansea West 46.0% of Gower
9.7% of Swansea East
Neath 100% of Neath 41.2% of Aberavon
Swansea East 90.3% of Swansea East 22.0% of Gower
16.9% of Swansea West