Wales: New Constituency Boundaries 2013

Each new seat can be described as a combination of parts of old seats. These table show this decomposition. The winner of the old seat at the 2010 election is shown by party colour, as is the implied winner of the new seat.

The implied results are now calculated using the local election results for the wards which make up each old seat. This should be more accurate than the earlier implied results which assumed each constituency was homogeneous.


New seatPrimary componentSecondary component(s)
Alyn and Deeside 100% of Alyn and Deeside 34.8% of Delyn
Conwy and Colwyn 72.7% of Clwyd West 70.4% of Aberconwy
Denbigh and Montgomeryshire North 56.7% of Clwyd South 45.8% of Montgomeryshire
27.3% of Clwyd West
19.7% of Vale of Clwyd
Flint and Denbighshire North 80.3% of Vale of Clwyd 65.2% of Delyn
Wrexham Maelor 100% of Wrexham 43.3% of Clwyd South


New seatPrimary componentSecondary component(s)
Caerfyrddin 92.0% of Carmarthen East and Dinefwr 41.0% of Carmarthen West and Pembrokeshire South
Ceredigion and Pembrokeshire North 100% of Ceredigion 24.2% of Preseli Pembrokeshire
8.0% of Carmarthen East and Dinefwr
Llanelli 100% of Llanelli 31.7% of Gower
Pembrokeshire South 75.8% of Preseli Pembrokeshire 59.0% of Carmarthen West and Pembrokeshire South


New seatPrimary componentSecondary component(s)
Blaenau Gwent 100% of Blaenau Gwent 43.6% of Islwyn
Caerphilly 90.5% of Caerphilly 36.0% of Islwyn
Monmouthshire 87.5% of Monmouth 30.8% of Newport East
Newport 69.2% of Newport East 57.0% of Newport West
Torfaen 100% of Torfaen 12.5% of Monmouth
11.0% of Newport West


New seatPrimary componentSecondary component(s)
Gwynedd 100% of Dwyfor Meirionnydd 54.4% of Arfon
15.7% of Aberconwy
Ynys Mon and Bangor 100% of Ynys Mon 45.6% of Arfon
14.0% of Aberconwy

Mid Glamorgan

New seatPrimary componentSecondary component(s)
Bridgend 100% of Bridgend 26.6% of Ogmore
Merthyr Tydfil, Rhumney and Lower Cynon 100% of Merthyr Tydfil and Rhymney 27.9% of Cynon Valley
9.5% of Caerphilly
4.6% of Islwyn
Pontypridd 90.1% of Pontypridd 19.3% of Ogmore
14.9% of Cynon Valley
8.0% of Rhondda
Rhondda and Aberdare 92.0% of Rhondda 57.2% of Cynon Valley


New seatPrimary componentSecondary component(s)
Brecon, Radnor and Montgomery 100% of Brecon and Radnorshire 54.2% of Montgomeryshire

South Glamorgan

New seatPrimary componentSecondary component(s)
Cardiff Central 90.8% of Cardiff Central 24.7% of Cardiff North
Cardiff North and Gwent South West 67.1% of Cardiff North 32.0% of Newport West
15.8% of Islwyn
Cardiff South and Penarth 95.2% of Cardiff South and Penarth 9.2% of Cardiff Central
Cardiff West 100% of Cardiff West 9.9% of Pontypridd
8.2% of Cardiff North
Vale of Glamorgan 100% of Vale of Glamorgan 4.8% of Cardiff South and Penarth

West Glamorgan

New seatPrimary componentSecondary component(s)
Aberavon and Ogmore 86.5% of Aberavon 54.0% of Ogmore
Gower and Swansea West 73.2% of Swansea West 46.7% of Gower
Neath and the Swansea Valley 100% of Neath 11.8% of Gower
13.5% of Aberavon
8.1% of Swansea East
Swansea East 91.9% of Swansea East 26.8% of Swansea West
9.8% of Gower