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The Prime Minister has told BBC Wales he is unsure if he will be visiting Caerphilly for the Senedd by-election campaign.

Labour is battling to retain the seat following the death of Hefin David last month.

Voters go to the polls on October 23.

When asked if he was going to Caerphilly, Sir Keir Starmer told BBC Wales: “I don’t know whether I’m going to Caerphilly. It’s obviously coming up very soon and we’ve got our party conference next week.”

During any election of significance, it is usually the case that big party figures visit to give campaigns a boost.

However, Sir Keir’s standing has been called into question with recent opinion polls, and policies such as the scrapping of the winter fuel payment proving unpopular.

Given that context, a visit from the Prime Minister could be seen as being more of a hindrance than a help to Labour candidate Richard Tunnicliffe.

Speaking to Caerphilly Observer at Labour’s campaign launch on September 8, the First Minister said she was not expecting Sir Keir to make an appearance.

Eluned Morgan said: “I shouldn’t think so. Generally the Prime Minister doesn’t involve himself in by-elections, so that’s unlikely but I think it’s really important also to recognise this is an election for the Senedd. So I’m very keen to make sure it keeps focused on the things within the Senedd’s control.”

Plaid Cymru leader Rhun ap Iorwerth, posting on X, said it was “baffling that campaigning in this by-election isn’t in the PM’s diary already”.

The national picture

Although Caerphilly County Borough contains both the Caerphilly and Islwyn Senedd constituencies, only voters in Caerphilly will go to the polls on October 23.

Four main parties – Labour, Plaid Cymru, Welsh Conservatives and Reform UK – have now named their candidates, with the Liberal Democrats and Gwlad also expected to stand.

This by-election is shaping up to be one of the most closely watched contests since devolution, not only because of the circumstances that triggered it, but also because of the wider shifts in Welsh politics.

An ITV Cymru Wales/YouGov poll, published last week, suggests Plaid Cymru and Reform UK are now in a two-way battle for first place across Wales, with Labour relegated to third – the weakest position the party has found itself in since the Senedd was created.

If repeated at the next Senedd election in May 2026, Plaid Cymru would emerge as the largest party with 38 seats under the new 96-member chamber. Reform would make a dramatic breakthrough but would still be some way from government.

Poll snapshot
Plaid Cymru – 30%
Reform UK – 29%
Labour – 14%
Conservatives – 11%
Liberal Democrats – 6%
Green Party – 6%
Other – 4%
_{Source: ITV Wales/ YouGov MRP Model}

Budget crisis

At stake is not just a seat but the future of the Welsh Government’s budget.

At the last Senedd election in 2021, Labour secured 30 of 60 seats – enough to form a government but short of a majority. To get its budgets through, Labour relied on Plaid Cymru’s support for the first three years, and on the sole Liberal Democrat, Jane Dodds, for the most recent one.

If Labour loses Caerphilly, even Ms Dodds’ backing would not be enough to pass the next budget. Plaid Cymru and the Conservatives have already ruled out deals, while Reform has said it would not support a Labour plan.

That raises the prospect, under Senedd rules, of up to £4 billion in Welsh Government spending being put at risk if no budget is passed – meaning cuts to local services.

Confirmed by-election candidates so far

• Welsh Liberal Democrats – Steve Aicheler
• Gwlad – Anthony Cook
• Wales Green Party – Gareth Hughes
• Welsh Conservatives – Gareth Potter
• Reform UK – Llŷr Powell
• Richard Tunnicliffe – Labour
• Lindsay Whittle – Plaid Cymru

Register to vote in the Caerphilly by-election

Voters in Caerphilly will head to the polls on Thursday 23 October 2025 to elect a new Senedd Member. Polling stations will be open from 7am to 10pm.

To take part, you must be registered to vote. You can do this online at Register to vote. The deadline is midnight on Tuesday October 7, 2025.

• You must:
• be registered to vote
• be 16 or over on polling day
• live in the Caerphilly Constituency
• not be legally excluded from voting

If you are unsure whether you are registered, contact Electoral Services at Bargoed House, 1 St Gwladys Way, Bargoed, CF81 8AB, email electoralservices@caerphilly.gov.uk, or call 01443 866586.

Voting by post: Applications for postal votes must be received by 5pm on Wednesday 8 October 2025.

Voting by proxy: If you want someone else to vote on your behalf, you must apply by 5pm on Wednesday October 15. In certain circumstances, emergency proxy applications can be made after this deadline.