Merthyr Tydfil and Aberdare
Wales · County constituency
About the Merthyr Tydfil and Aberdare constituency
Merthyr Tydfil and Aberdare is a county constituency in Wales, spanning parts of Merthyr Tydfil, Rhondda Cynon Taf and neighbouring councils. The sitting MP is Gerald Jones (Labour), first elected in May 2015.
At the 2024 general election, Labour won Merthyr Tydfil and Aberdare with 44.8% of the vote, ahead of Reform UK on 23.7%, a majority of 7,447 votes. Turnout was 47.3%.
If a general election were held today, PollCheck's projection at the current seven-poll average has Reform UK on 29.7% and Labour on 26.1% in Merthyr Tydfil and Aberdare, a margin of 3.6 points, a projected change from Labour since 2024. The projection updates automatically as new polls are added.
Demographically, Merthyr Tydfil and Aberdare is a Leave-leaning area (an estimated 55.6% voted Leave in 2016). About 25.4% of residents hold a degree, 64.2% of homes are owner-occupied, and the seat has a median age of about 42 (2021 Census).
Across the most recent general elections on record here, the seat has been won by Labour each time.
Who lives in Merthyr Tydfil and Aberdare? Constituency demographics
From the 2021 Census and 2016 EU referendum estimates. Constituency-level data on 2024 boundaries.
How did Merthyr Tydfil and Aberdare vote in 2024 and how would it vote now?
2024 vote shares from the HoC Library. Current projection is at the 7-poll average.
2024 general election
Current projection
Map of Merthyr Tydfil and Aberdare
Switch between ward-level 2024 election winners and a demographic view. Ward winners are Britain Elects' / New Statesman modelled estimates with an average ~4pp margin of error per ward. The demographic view splits the seat into small neighbourhoods (around 1,500 residents each, from the 2021 Census). Hover any area for detail.
How Merthyr Tydfil and Aberdare voted at the Senedd election (7 May 2026)
Merthyr Tydfil and Aberdare sits almost entirely within the Senedd constituency of Pontypridd Cynon Merthyr. Senedd elections use a closed-list proportional system; each Senedd seat returns six members.
| Senedd constituency | Share of Merthyr Tydfil and Aberdare | Winner | Runner-up | Seats (6 per constituency) |
|---|---|---|---|---|
| Pontypridd Cynon Merthyr | 99% | Plaid Cymru 39.5% | Reform UK 30.6% | 3 Plaid Cymru, 2 Reform UK, 1 Labour |
Senedd 2026 results from official declarations. Overlap percentages are area-based using the post-2024 Westminster boundary against the new 16-seat Senedd boundary.
Merthyr Tydfil and Aberdare within Merthyr Tydfil and Rhondda Cynon Taf
Merthyr Tydfil and Aberdare crosses multiple council boundaries: Merthyr Tydfil (59%), Rhondda Cynon Taf (41%). English councils rotate their election cycles and none of the constituent councils were due to vote in 2026, so the figures below show the most recent ward result available for each ward.
Council overlap
| Council | Share of seat |
|---|---|
| Merthyr Tydfil | 59% |
| Rhondda Cynon Taf | 41% |
Recent council by-elections
Council ward by-elections held inside this seat, most recent first. The result column shows which party won; the share column shows the top three parties’ vote shares on the day.
| Date | Ward | Result | Top 3 vote shares |
|---|---|---|---|
| 25 Jun 2026 | Dowlais & Pant | Lab GAIN from Ind | Lab 40% Other 24% Ref 18% |
| 6 Sep 2024 | Bedlinog and Trelewis | Lab GAIN from Ind | — |
Most recent council ward results
Latest council winner per ward. Where the council held a May 2026 election, those results are shown; otherwise we show the most recent available ward result (via DCLEAPIL, 2014-2024), or, where the seat was uncontested at the last election, the current sitting councillor from OpenCouncilData. The "Shift since GE2024" column is only computed for May 2026 results - earlier council votes pre-date the GE, so no directional shift is shown.
| Ward | GE2024 winner | Latest council winner | Shift since GE2024 | Turnout |
|---|
Projection trajectory
PollCheck's projection for Merthyr Tydfil and Aberdare at each of the last 60 GB polls. Hover the chart for the underlying poll details.
Who has won Merthyr Tydfil and Aberdare at past general elections?
2024 result is on current boundaries. The 2019 row is the UK Parliament's notional recalculation onto the 2024 boundaries (directly comparable to 2024). The 2010, 2015 and 2017 rows are on the boundaries in force at the time and aren't directly comparable.
| Year | Result | MP | Lab | Con | LD | Majority | Turnout |
|---|---|---|---|---|---|---|---|
| 2010predecessor | Lab hold | Ann Clwyd Cynon Valley MP | 52.5% | 10.1% | 13.8% | 9,617 | 59.0% |
| 2015predecessor | Lab hold | Ann Clwyd Cynon Valley MP | 47.7% | 12.1% | 2.7% | 9,406 | 59.3%+0.3 |
| 2017predecessor | Lab hold | Ann Clwyd Cynon Valley MP | 61.0% | 19.4% | 1.8% | 13,238 | 62.0%+2.7 |
| 2019notional | Labour winner | Beth Winter Cynon Valley MP, pre-review boundary | 51.7% | 20.6% | 3.3% | 13,410 | 57.6% |
| 2024 | Lab hold | Gerald Jones | 44.8% | 7.6% | 3.6% | 7,447 | 47.3%-10.3 |
Merthyr Tydfil and Aberdare was created or substantially redrawn by the 2023 boundary review. Pre-2024 rows below are for the predecessor seat Cynon Valley (the seat that covered most of this area), so vote shares and majorities aren’t directly comparable to the post-2024 figures.
Constituencies most like Merthyr Tydfil and Aberdare
Five seats with similar demographic profiles to Merthyr Tydfil and Aberdare. Politics shown for context.
- ↓Graduate25.4 / 23.7vs 33.7
- ↑No quals26.0 / 27.0vs 18.0
- ↓Employed52.5 / 50.4vs 57.3
- ↓Graduate25.4 / 27.3vs 33.7
- ↓Employed52.5 / 52.3vs 57.3
- ↓Private rent16.1 / 15.4vs 20.2
- ↓Graduate25.4 / 27.2vs 33.7
- ↓Private rent16.1 / 17.2vs 20.2
- ↑No quals26.0 / 21.7vs 18.0
- ↓Graduate25.4 / 25.7vs 33.7
- ↓Private rent16.1 / 16.0vs 20.2
- ↓Employed52.5 / 53.6vs 57.3
- ↓Graduate25.4 / 26.9vs 33.7
- ↓Private rent16.1 / 13.1vs 20.2
- ↑No quals26.0 / 21.4vs 18.0
What would change this seat?
Move the sliders to set national vote shares. The per-seat projection updates live. Reset returns to the current 7-poll average.
Related
Sources
- 2024 general election results · UK Parliament Election Results portal and House of Commons Library briefing CBP-10009.
- Notional 2019 results on 2024 boundaries · UK Parliament Election Results portal. Recalculated by Parliament; carries assumptions about how 2019 voters would have distributed across the redrawn boundaries.
- Historic general election results (2010-2017) · House of Commons Library historic results files (on the boundaries in force at the time).
- Ward-level GE2024 estimates · Britain Elects / New Statesman - article by Ben Walker, underlying spreadsheet. Modelled from constituency totals; average ~4pp per-ward MoE.
- May 2026 council ward results · Democracy Club via PollCheck's locals 2026 dataset.
- Earlier council ward results (2014-2024) · DCLEAPIL v1.0 (Jason Leman, drawing on Andrew Teale's LEAP dataset and Democracy Club).
- Demographics · ONS Census 2021 (England and Wales), aggregated to constituency level using the ONS LSOA21 -> PCON24 best-fit lookup.
- EU referendum 2016 estimates · Constituency-level Leave vote estimates (Hanretty 2017 method).
- MP details and Cabinet roles · UK Parliament Members API. MP photos are fetched live from the same source.
- Boundary geometry and lookups · ONS Open Geography Portal (PCON24 boundaries, LSOA21 boundaries, LSOA21-WD24-LAD24 best-fit lookup).
- Current projection and trajectory · PollCheck's demographic swingometer applied to the rolling 7-poll average from aggregated GB polls. Not a true MRP - vote-share movements are applied through per-constituency sensitivity multipliers derived from demographic regressions.
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