New constituency-level analysis from YouGov’s July 2025 MRP polling confirms that Reform UK continues to lead in South West Wales, but small vote share shifts point to signs of life for Labour in several key seats.
The updated data follows Swansea Bay News’ original projection last month based on an MRP forecast by research group More in Common, which charted Reform UK’s dramatic rise across the region. While the new numbers show the party maintaining its hold in nine of ten constituencies, Labour has recovered modest ground — most notably in Llanelli and Swansea West.
The full breakdown is shown below, with vote share changes since the previous projection in early July:
Westminster projections: Reform gains hold, Labour rebounds slightly
| Constituency | Projected Winner | Reform UK | Labour | Plaid Cymru | Conservative | Lib Dem | Green | Others | Outcome | Change Summary |
|---|---|---|---|---|---|---|---|---|---|---|
| Llanelli | Reform UK | 41% | 18% | 26% | 5% | 4% | 2% | 4% | Reform Hold | Reform ↓3pts, Labour ↑3pts |
| Swansea West | Reform UK | 30% | 22% | 20% | 9% | 11% | 5% | 3% | Reform Hold | Reform ↑1pt, Labour ↑2pts |
| Neath & Swansea East | Reform UK | 27% | 24% | 21% | 7% | 7% | 4% | 10% | Reform Hold | Reform ↑1pt, Labour ↑1pt |
| Gower | Reform UK | 33% | 28% | 3% | 16% | 3% | 5% | 12% | Reform Hold | Reform ↑1pt, Labour ↓2pts |
| Bridgend | Reform UK | 42% | 23% | 14% | 5% | 7% | 5% | 4% | Reform Hold | Reform ↓2pts, Labour ↑1pt |
| Aberafan Maesteg | Reform UK | 40% | 20% | 14% | 6% | 13% | 3% | 4% | Reform Hold | Reform ↑1pt, Labour ↓1pt |
| Caerfyrddin | Plaid Cymru | 38% | 13% | 38% | 8% | 2% | 6% | 5% | Plaid Hold | Plaid ↓1pt, Labour ↑1pt |
| Ceredigion Preseli | Plaid Cymru | 50% | 9% | 50% | 10% | 3% | 5% | 3% | Plaid Hold | Plaid ↓2pts, Reform ↓2pts |
| Mid & South Pembrokeshire | Reform UK | 35% | 18% | 6% | 25% | 6% | 3% | 7% | Reform Hold | Reform ↑1pt, Labour ↓1pt |
| Brecon, Radnor & Cwm Tawe | Reform UK | 33% | 17% | 17% | 9% | 18% | 5% | 1% | Reform Hold | Reform ↓1pt, Labour ↑1pt |
Reform UK’s overall vote share remains robust, but Labour has managed to reverse some of its earlier decline. The Green Party also shows slight upward movement, particularly in Swansea West and Neath & Swansea East. The Liberal Democrats and Conservatives remain in single digits across most seats, with Plaid Cymru continuing to defend its heartland constituencies in Caerfyrddin and Ceredigion Preseli.
Updated Senedd projections for South West Wales
A parallel projection for the 2026 Senedd election, using the D’Hondt method to allocate seats across newly drawn regional boundaries, reveals that Reform UK is poised to win at least two seats in every South West Wales region.
| Senedd Constituency | Composed of Parliamentary Seats | Projected MSs (by party) | Change Summary |
|---|---|---|---|
| Gŵyr Abertawe | Swansea West + Gower | 2 Reform, 2 Labour, 1 Plaid, 1 Lib Dem | No change |
| Brycheiniog Tawe Nedd | Brecon, Radnor & Cwm Tawe + Neath & Swansea East | 2 Reform, 2 Labour, 1 Plaid, 1 Green | “Other” replaced by Green |
| Afan Ogwr Rhondda | Aberafan Maesteg + Rhondda and Ogmore | 3 Reform, 2 Labour, 1 Lib Dem | No change |
| Sir Gaerfyrddin | Llanelli + Caerfyrddin | 3 Plaid, 2 Reform, 1 Labour | No change |
| Ceredigion Penfro | Ceredigion Preseli + Mid and South Pembrokeshire | 3 Reform, 2 Conservative, 1 Labour | No change |
| Pen-y-bont Bro Morgannwg | Bridgend + Vale of Glamorgan | 2 Labour, 2 Reform, 1 Conservative, 1 Plaid | No change |
While there are no changes in overall seat allocation since the previous projection, a Green gain in Brycheiniog Tawe Nedd suggests growing support among progressive voters under the new proportional system.
Momentum holds — but the race tightens
The broader trend is clear: Reform UK remains dominant across South West Wales, particularly in seats with high anti-incumbent sentiment. Labour’s gains, though limited, indicate potential for a more competitive landscape — particularly if national party dynamics shift.
Plaid Cymru continues to hold ground in its strongholds but faces growing pressure from both Reform and Labour. Smaller parties such as the Greens and Liberal Democrats may benefit from increased voter awareness of the Senedd’s proportional system, especially in more urban regions.
