General election forecast

Cardiff West

Predicted winner: Reform UK with 23.6% of the vote, a 0.1pp margin over Labour.

wales · wales

Predicted vote share

How the model expects this constituency to vote

Reform UK

23.6% +11.0pp

Labour

23.5% +23.5pp

Plaid Cymru

20.2% +20.2pp

Green Party

12.3% +5.2pp

Conservative

12.1% +12.1pp

Lib Dem

4.8% +0.5pp

Propel

2.2% -0.1pp

SNP

0.6% +0.6pp

Independent

0.5% -0.0pp

Heritage Party

0.2% +0.0pp

Other

0.0% 0.0pp

Coloured number is the swing from the 2024 general election result.

Sitting MP

Alex Barros-Curtis

Party: Labour Party
Tenure: 1.9 years (since 2024-07-04)
Status: standing again

What happened on 4 July 2024

Candidate	Party	Votes	Share
Alex Barros-Curtis	Labour Party	16,442	36.7%
Kiera Duncan Marshall	Plaid Cymru - The Party of Wales	9,423	21.1%
James Robert Hamblin	Conservative and Unionist Party	6,835	15.3%
Peter Meireon Hopkins	Reform UK	5,626	12.6%
Jess Ryan	Green Party	3,157	7.1%
Manda Rigby	Lib Dem	1,921	4.3%
Neil John McEvoy	Propel	1,041	2.3%
John Ernest Urquhart	Independent	241	0.5%

Source: Returning officer declaration

How accurate is the model here?

Our 2024 backtest for this constituency

We replayed the same model architecture against the 4 July 2024 general election using only the data a forecaster running the model in May 2024 would have known. Here's what it would have predicted for Cardiff West, and what actually happened.

✓ Winner called correctly , predicted Labour, actual Labour. Major-party MAE: 6.18pp, the average gap between our predicted vote share and the actual share, per major party.

Predicted

Labour

56.9%

Plaid Cymru

11.1%

Conservative

10.4%

Reform UK

9.8%

Green Party

5.3%

Lib Dem

5.6%

Propel

0.0%

Independent

0.0%

Actual on 4 July 2024

Labour

36.7% +20.2pp

Plaid Cymru

21.1% -9.9pp

Conservative

15.3% -4.8pp

Reform UK

12.6% -2.8pp

Green Party

7.0% -1.8pp

Lib Dem

4.3% +1.3pp

Propel

2.3% -2.3pp

Independent

0.5% -0.5pp

Positive gap = we predicted that party would win more share than they did. See the full GE backtest across all 650 seats for the model's national accuracy.

How this forecast was built

GE2024 Baseline. Actual GE2024 result in Cardiff West
National Swing (Strong Transition Model). Multiplicative bounded swing, losers shed in proportion to local share, gainers absorb pro-rata national gain. Replaces additive UNS.
BES MRP Prior. Baseline blended with BES Wave 1-30 wales prior at weight 5%
Normalise. Shares scaled to 100%

Read the full general election methodology →