Starmer concedes defeat - Labour relegated to third

Prime Minister Sir Keir Starmer sits with Ukraine’s President Volodymyr Zelensky facing a screen with other participants joining by video link during a meeting of the ‘coalition of the willing’ allies, at the Foreign, Commonwealth and Development Office (FCDO) in Westminster, London. The UK and France have led efforts to bring together countries willing to provide security for Ukraine if a ceasefire is agreed. Picture date: Friday October 24, 2025. Henry Nicholls

Sir Keir Starmer (Labour) admitted he was "deeply disappointed" by Labour's devastating loss in the Welsh Parliament by-election and acknowledged the party "clearly need to do much more". The Prime Minister said both UK and Welsh administrations must "reflect and regroup" after Thursday's result, which saw Plaid Cymru claim victory with Reform UK finishing second.

When pressed about potential resignation if Labour's fortunes don't improve before May's Senedd elections, Starmer told reporters: "In relation to the by-election, look, I'm deeply disappointed in the results. I'm not going to suggest otherwise." He confirmed speaking with the First Minister and emphasised the need to "double down on delivery in Wales".

Historic Labour stronghold falls

Thursday's by-election delivered a crushing blow to Labour, relegating the party to third place in what had been a stronghold for nearly a century. Plaid Cymru's Lindsay Whittle secured 15,961 votes - representing 47% of the total and an increase of almost 19% from the 2021 constituency result.

Reform candidate Llyr Powell achieved a dramatic surge to 12,113 votes, compared to just 495 four years earlier. Labour's Richard Tunnicliffe managed only 3,713 votes, a steep decline from 13,289 in 2021, while Conservative candidate Gareth Potter received just 690 votes.

Political earthquake ahead of May

Polling expert Sir John Curtice warned the result showed Labour was in "severe trouble" in Wales, with May's Senedd election potentially ending Labour's grip on power for the first time since devolution in 1999. The timing proves particularly challenging as the Welsh Government faces an upcoming budget vote that had already caused anxiety for the Labour administration.

Labour lacks a majority in the Senedd and previously required opposition support to pass its March budget by the narrowest of margins. Losing the Caerphilly seat makes the next budget vote even more precarious for the governing party.

Leaders react to seismic shift

Labour First Minister Eluned Morgan described the by-election as conducted under "the toughest conditions" amid "difficult headwinds nationally", promising to learn lessons and "come back stronger". Plaid Cymru leader Rhun ap Iorwerth declared his party had become the "real choice" for Wales, claiming voters had chosen "hope over division and progress over the tired status quo" by backing Plaid's "positive, pro-Wales vision".

Ap Iorwerth proclaimed the result demonstrated "Plaid is no longer just an alternative" but rather "the real choice for Wales, the only party able to stop billionaire-backed Reform and offering a better future that works for everyone".

Sources used: "PA Media" Note: This article has been created with Artificial Intelligence (AI).