Plaid Cymru Triumphs in Caerphilly, Ending Labour Century-Long

Published: 24 October 2025. The English Chronicle Desk. The English Chronicle Online.

In a dramatic and historic political upset, Labour has lost its long-standing dominance in Caerphilly, a constituency it had held for over a century. The by-election victory by Plaid Cymru represents a significant shift in Welsh politics, shaking the foundations of Sir Keir Starmer’s leadership and highlighting a collapse of support in what has traditionally been a Labour heartland.

The by-election result was a crushing blow for Labour, with Plaid Cymru securing 15,961 votes, nearly doubling their 2021 tally of 8,211. Reform UK, which had been polling strongly and was expected to mount a serious challenge, came second with 12,113 votes. Labour, in contrast, saw its vote share collapse from 35 percent to a mere 11 percent, translating to only 3,713 ballots. Analysts suggest tactical voting played a role, though the result also reflects a broader decline in confidence in Labour’s leadership and local engagement.

Plaid Cymru’s candidate, Lindsay Whittle, celebrated a hard-fought victory on his 14th attempt, receiving rapturous applause from supporters. In his victory speech, Whittle described the outcome as marking an “exciting time for politics in Wales” and hailed the beginning of a “new leadership” that aims to bring meaningful change to the constituency. Rhun ap Iorwerth, leader of Plaid Cymru, echoed this sentiment, emphasizing that the voters had chosen “hope over division, and progress over the tired status quo,” supporting Plaid Cymru’s pro-Wales vision and local advocacy.

For Reform UK, the result was bittersweet. While failing to secure the seat, the party can take heart from the growth in its support base, which rose from 2 percent to 36 percent in just four years. Party leader Nigel Farage did not attend the count, but Reform’s candidate, Llŷr Powell, defended his campaign, pointing to the surge in backing and criticizing Starmer for his perceived lack of engagement in the Caerphilly constituency. Powell stated, “The person who should be embarrassed is Keir Starmer, who failed to turn up here because he doesn’t care about the constituency of Caerphilly, he doesn’t care about the people of Wales.”

Welsh Labour leader Baroness Morgan acknowledged the setback while emphasizing responsibility and resilience. “This was a by-election in the toughest of circumstances and in the midst of difficult headwinds nationally,” she said. “I want to thank our candidate, Richard Tunnicliffe, a good man who stood because of his desire to serve his community. I congratulate Lindsay Whittle on his victory tonight. He returns to the Senedd, continuing his many decades of elected service to people in Caerphilly.” She added that Welsh Labour is listening to the frustrations expressed on the doorsteps and will strive to address concerns to return stronger in future elections.

The by-election loss also underscores Labour’s declining grip on devolved power in Wales. With this defeat, the party now holds 29 seats in the 60-seat Senedd, effectively losing its outright majority and increasing reliance on other members to secure a working majority. This development complicates the Welsh Government’s ability to pass its budget through Parliament, raising the stakes for upcoming legislative negotiations and potentially leading to difficult decisions regarding public spending.

The broader electoral landscape in the Senedd reflects a near tie between Plaid Cymru and Reform UK, both hovering around 30 percent support, while Labour lags at approximately 14 percent. Polling data suggests that only about one-quarter of Labour voters from the previous general election intend to support the party in the next Senedd vote, signaling potential for further upheaval in May’s elections.

Political analysts have emphasized the historic significance of Labour’s defeat in Caerphilly. Once a bastion of Labour’s influence, the constituency has been emblematic of the party’s deep roots in the former mining communities of South Wales. Its loss not only represents a symbolic collapse but also provides a warning of growing voter dissatisfaction in other Labour strongholds across Wales.

Plaid Cymru’s win reflects both effective local campaigning and the resonance of its pro-Wales agenda. Lindsay Whittle’s deep understanding of the constituency and long-standing engagement with local communities were pivotal in securing voter confidence. This outcome may embolden Plaid Cymru as it seeks to expand its influence in the Senedd and challenge Labour’s dominance in upcoming elections.

The by-election result also raises questions for Labour’s national strategy under Keir Starmer. While the party’s leadership had managed expectations by characterizing the campaign as “tough,” the scale of the defeat indicates systemic challenges, including weakened voter engagement and competition from both nationalist and reformist parties. With Welsh politics becoming increasingly competitive, Labour faces pressure to reconnect with its traditional base while addressing contemporary concerns of younger and more diverse voters.

For Reform UK, despite falling short of victory, the surge in support is a notable achievement. The party has steadily increased its influence, positioning itself as a growing alternative in Wales. The increase in voter share from 2 percent to 36 percent over four years signals the electorate’s openness to new political narratives and reflects a broader trend of fluidity in traditional party loyalties.

The immediate implications of the Caerphilly by-election extend beyond local politics. Labour’s loss has national resonance, as it highlights vulnerabilities that could affect general election strategies and influence public perception of the party’s leadership effectiveness. Meanwhile, Plaid Cymru’s growing momentum demonstrates the rising appeal of nationalist platforms and the importance of local representation in shaping voter behavior.

As Welsh politics enters this new chapter, all parties are recalibrating their approaches in light of the Caerphilly result. Labour faces the urgent task of rebuilding trust and articulating a compelling vision to recapture its base. Plaid Cymru, buoyed by its landmark victory, will likely seek to leverage its momentum to secure additional gains, while Reform UK continues to consolidate support among disenchanted voters. The by-election serves as a clear reminder that political landscapes are in flux and that historical dominance is never guaranteed.