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 2015 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 Seats | New Seats | Change | Disappear | Switch Out | Switch In | Fresh | |
|---|---|---|---|---|---|---|---|
| Con | 11 | 7 | -4 | -4 | -2 | 2 | 0 |
| Lab | 25 | 18 | -7 | -6 | -3 | 2 | 0 |
| Lib | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
| Ukip | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Green | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Nat | 3 | 3 | 0 | -1 | 0 | 1 | 0 |
| Min | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Total | 40 | 29 | -11 | -11 | -5 | 5 | 0 |
The table shows how the various changes affect each party in this region. 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:
- Disappear : seats which have disappeared as they are broken into small fragments
- Switch Out : seats lost because their political make-up has altered
- Switch In : seats gained because their political make-up has altered
- Fresh : freshly created new seats which are made up of small fragments of old seats
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: Bridgend; Cardiff North; Clwyd South; Vale of Clwyd; Ynys Mon.
The new seats which are gained from another party are: Bridgend and Vale of Glamorgan West; Cardiff North; Clwyd South and Montgomeryshire North; Flint and Rhuddlan; Ynys Mon and Arfon.
Clwyd
| New seat | Primary component | Secondary component(s) |
|---|---|---|
| Alyn and Deeside | 100% of Alyn and Deeside | 30.8% of Delyn |
| Clwyd South and Montgomeryshire North | 56.2% of Clwyd South | 49.6% of Montgomeryshire
23.4% of Clwyd West
7.2% of Dwyfor Meirionnydd
3.0% of Vale of Clwyd
|
| Colwyn and Conwy | 69.2% of Clwyd West | 80.8% of Aberconwy |
| Flint and Rhuddlan | 71.0% of Vale of Clwyd | 69.2% of Delyn |
| Wrexham Maelor | 100% of Wrexham | 43.8% of Clwyd South |
Dyfed
| New seat | Primary component | Secondary component(s) |
|---|---|---|
| Carmarthenshire | 92.4% of Carmarthen East and Dinefwr | 40.8% of Carmarthen West and Pembrokeshire South |
| Ceredigion and North Pembrokeshire | 100% of Ceredigion | 24.0% of Preseli Pembrokeshire
7.6% of Carmarthen East and Dinefwr
8.2% of Montgomeryshire
|
| Llanelli and Lliw | 100% of Llanelli | 32.8% of Gower |
| Pembrokeshire South | 76.0% of Preseli Pembrokeshire | 59.2% of Carmarthen West and Pembrokeshire South |
Gwent
| New seat | Primary component | Secondary 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 seat | Primary component | Secondary component(s) |
|---|---|---|
| Clwyd North and Gwynedd | 92.8% of Dwyfor Meirionnydd | 26.0% of Vale of Clwyd
25.4% of Arfon
19.2% of Aberconwy
7.5% of Clwyd West
|
| Ynys Mon and Arfon | 100% of Ynys Mon | 74.6% of Arfon |
Mid Glamorgan
| New seat | Primary component | Secondary component(s) |
|---|---|---|
| Bridgend and Vale of Glamorgan West | 100% of Bridgend | 20.2% of Vale of Glamorgan |
| 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 Port Talbot | 100% of Ogmore | 38.3% of Aberavon |
| Rhondda and Llantrisant | 100% of Rhondda | 45.1% of Pontypridd |
Powys
| New seat | Primary component | Secondary component(s) |
|---|---|---|
| Brecon, Radnor and Montgomery | 100% of Brecon and Radnorshire | 42.2% of Montgomeryshire |
South Glamorgan
| New seat | Primary component | Secondary component(s) |
|---|---|---|
| Cardiff North | 89.0% of Cardiff North | 37.6% of Cardiff Central
4.8% of Pontypridd
|
| Cardiff South and East | 54.3% of Cardiff South and Penarth | 62.4% of Cardiff Central
11.0% of Cardiff North
|
| Cardiff West | 100% of Cardiff West | 16.1% of Cardiff South and Penarth |
| Vale of Glamorgan East | 79.8% of Vale of Glamorgan | 29.6% of Cardiff South and Penarth |
West Glamorgan
| New seat | Primary component | Secondary component(s) |
|---|---|---|
| Gower and Swansea West | 83.1% of Swansea West | 57.9% of Gower |
| Neath and Aberavon | 100% of Neath | 47.0% of Aberavon |
| Swansea East | 100% of Swansea East | 16.9% of Swansea West
14.7% of Aberavon
9.3% of Gower
|
