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Plaid Cymru lead ahead of Caerphilly by-election – poll

05 Sep 2025 3 minute read
Caerphilly. Photo by Richard Szwejkowski is licensed under CC BY-SA 2.0.

Plaid Cymru is the frontrunner to win the upcoming Caerphilly Senedd by-election, according to new polling which shows a sharp fall in support for both Labour and the Conservatives.

The survey by Find Out Now projects Plaid taking 35% of the vote, ahead of Reform UK on 29% and Labour trailing in third on 24%.

The result would mark a significant shift in a constituency long regarded as a Labour stronghold.

The by-election, set for 23 October, follows the sudden death of Labour MS Hefin David. It will be the final contest fought under first-past-the-post before the Senedd moves to a new proportional system next year.

Candidate

Plaid has already confirmed its candidate, veteran councillor and former regional Assembly Member Lindsay Whittle, who finished second in last year’s general election.

Speaking after the poll’s publication, Plaid leader Rhun ap Iorwerth said the findings reflected what the party was hearing on the ground: “People are fed up of being taken for granted by Labour and the Tories. A large majority don’t want Reform and their Trump-style brand of divisive politics, and they are turning to Plaid to send a message.”

Wayne David

Labour has yet to select a candidate after former MP Sir Wayne David ruled himself out despite pressure from party figures. Sir Wayne, who represented the constituency at Westminster for 23 years, said he would instead support “whoever she or he may be” to continue Hefin David’s work.

Reform UK is also yet to announce its candidate but has already set up a campaign base in Caerphilly town centre. Party insiders have dismissed speculation that former MP Mark Reckless could be in the running.

The by-election is seen as hugely significant by the three leading parties.

For Labour, retaining the seat would counter criticism of the UK party’s performance since taking power in Westminster. For Reform, a failure to make a breakthrough could puncture perceived momentum, while a Plaid Cymru win would underline its claims of growing support in former Labour heartlands ahead of the 2026 Senedd election.

The polling figures are calculated by the industry standard method, of a uniform national swing applied to the 2021 result in the constituency (the last time it was fought on these boundaries) compared with the most recent major national Senedd poll. The full poll is available here. 


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David Richards
David Richards
3 months ago

Cliche I know but the only poll that matters is the one on polling day. But Plaid have a excellent local candidate in Lindsay Whittle – who would certainly contrast favourably with the notorious carpetbagger Mark Reckless (if Reform do select him).

Dai Ponty
Dai Ponty
3 months ago
Reply to  David Richards

Reckless by name Reckless by nature not just him but the whole Party

hdavies15
hdavies15
3 months ago
Reply to  David Richards

Point well made David. People still get carried away by these mickey mouse pollsters. To get the win on polling day the party needs to work the streets right up to the final whistle.

Ken
Ken
2 months ago
Reply to  hdavies15

Right up to the final Whittle.

John Ellis
John Ellis
3 months ago

Encouraging to see that it isn’t Reform in the lead, at least if the findings of this poll are accurate.

andy w
andy w
3 months ago

Politics is changing rapidly and todays Reform conference will show their focus – sponsored by Heathrow Airport, so highlights no interest in Green / Sustainability issues.

A lot can happen before the Senedd election next year – if there was a massive jobs boost to Wales from an international organisation choosing Wales for expansion then the political focus may change from flags / economic migrants on boats etc.

James Edwards
James Edwards
3 months ago

Not surprised by this news at all as I said yesterday only the thick and the traitors support the far right English Nationalist Party and there aren’t anywhere near enough of those in the Rhymney Valley.

hdavies15
hdavies15
3 months ago
Reply to  James Edwards

Don’t be too presumptuous. These polls are meaningless. Any party wanting to win will have to work the streets and not get carried away on a wave of delusion.

Rob W
Rob W
3 months ago

This confirms what I suggested in a previous article, that this would be a two horse race between Plaid and Reform. So if anyone in Caerphilly is still considering voting for Labour, you know what you need to do if you don’t want Reform to win. As things stand, Labour are toast, so it’s no wonder they’re having trouble finding a sacrificial lamb to stand for election.

andy w
andy w
3 months ago
Reply to  Rob W

Rob, the focus in Wales is sadly too similar to England – personality / media profile and not growing the economy. All i see on LinkedIn is job creation linked to low-paid jobs – Tata funding to redeploy ex-Steelworkers spent on a cafe in Neath, Live Nation venue in Cardiff, Dublin based Amazon opening a Data Centre – so all taxes routed via a lower tax region; criticism of University management and no suggestions of how could manage better. http://www.gcre.wales needs £0.5billion to open – who will fund? A project like that will create very well-paid roles. Transport for Wales… Read more »

SundanceKid
SundanceKid
2 months ago
Reply to  Rob W

Yep. A vote for Labour is a vote for Reform. The same argument used by Labour against Plaid voters in recent years. Plaid Cymru need to hammer this message home.

Ken
Ken
2 months ago
Reply to  SundanceKid

It was true when Labour said it and it’s probably true now when Plaid say it. I imagine there are a lot of traditionally Labour-voting people in Caerphilly who a. know this, and b. are disillusioned with the Labour government in London. Also, Lindsay Whittle is a decent candidate.

Last edited 2 months ago by Ken
Paul
Paul
2 months ago
Reply to  SundanceKid

A vote for plaid is a vote for liebor

smae
smae
3 months ago

That is not a good sign for Labour at all… and seems to tie in with current polling predictions of how the Senedd elections might go…

Garycymru
Garycymru
3 months ago

Nice to see the population of this area are far more civilised and intelligent than those in Llanelli.

Ian
Ian
3 months ago

Reform will outspend the other parties and bus in supporters from England. They will be relying on ‘Google Maps’ a lot as they will not know the area & struggle with Welsh names (genuinely!). Caerphilly as a constituency has a lot of challenges and the Senedd certainly needs to step up in delivery next year for such areas, but a Reform MS will only create division and offer zero hope.

Gwyn Hopkins
Gwyn Hopkins
3 months ago

Good news. The key question Caerffili electors should ask in relation to the Senedd by-election on October 23rd is: Which candidate will best – with enthusiasm, determination and integrity – stand up for Caerffili and Wales if elected? In view of local candidate Lindsey Whittle’s undisputed record of excellent and conscientious service to the electors of Caerffili and to Wales for decades, it is virtually impossible to imagine any other candidate becoming anywhere near to being so deserving of becoming Caerffili’s Senedd Member. 

J jones
J jones
3 months ago

Whilst the conclusions are perfectly plausible. The analysis here doesn’t really amount to much. Whilst polls are perfectly valid, the truth is in Wales there just aren’t really enough of them publicly available to establish much of a trend. The one cited was nearly 3 months ago compared to Uk wide polls that are published almost every day. It’s not even the most recent one, there have been two subsequent polls that arguably paint a different picture. Yes they had smaller sample sizes but seems strange to ignore them given that one it seems was actually commissioned by Nation Cymru.… Read more »

Rob
Rob
2 months ago

Good news, but Plaid cannot be complacent and take this for granted. Regarding Mark Reckless does he not live in England? Hasn’t the law changed so that you now have to live in Wales to stand as a Senedd member?

SundanceKid
SundanceKid
2 months ago
Reply to  Rob

He is also a renowned anti-Welsh bigot. If he stands, Plaid need to make the utmost capital of this.

Ken
Ken
2 months ago
Reply to  Rob

For many Reform voters, Farage is the real candidate in every constituency. It doesn’t really matter who they put up.

Richard Lice
Richard Lice
2 months ago

Caerphilly will be subject to a saturation bombing raid by Reform .Residents can expect no peace in a post Hefin world .They couldn’t even wait until he was buried.
Reform seeking to appoint a Welsh policy adviser to be based in Westminster whilst the latest turncoat Jones seeking to curb powers at the Senedd.
It’s anyone but Reform

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