GLOBAL – The Welsh nationalist party, Plaid Cymru, secured a historic victory in a closely watched by-election for the Caerphilly constituency of the Welsh Parliament (Senedd) on Thursday, 23 October 2025, a result with significant implications for UK politics and lessons for electoral contests in Kenya. The winning candidate, Lindsay Whittle, a veteran local politician, defeated the right-wing populist party Reform UK in a contest that saw the governing Labour Party suffer a stunning collapse in one of its traditional strongholds.

The by-election, held to fill the seat of the late Labour member Hefin David who passed away in August 2025, ended over a century of Labour dominance in the area. Mr. Whittle secured 15,961 votes, representing 47.4% of the total, while Reform UK's candidate, Llŷr Powell, came in second with 12,113 votes (36.0%). The Labour candidate, Richard Tunnicliffe, finished a distant third with just 3,713 votes (11.0%), a dramatic decline from the party's 46% vote share in the 2021 Senedd election. The election was marked by an exceptionally high turnout of 50.4%, the highest ever for a Senedd by-election, indicating significant voter engagement.

A Tactical Vote Against Populism

Analysts suggest the outcome was heavily influenced by tactical voting, a strategy where citizens vote for a candidate who is not their first choice to prevent a less desirable outcome. In Caerphilly, it appears many traditional Labour supporters and other progressive voters coalesced around Plaid Cymru's Lindsay Whittle as the most viable candidate to defeat Reform UK. Polling data ahead of the vote indicated that nearly a third of those who voted Labour in 2021 planned to switch their vote to Plaid Cymru. This strategic voting effectively blocked the advance of Reform UK, a party known for its hardline stance on immigration and opposition to net-zero climate policies.

Plaid Cymru is a centre-left party advocating for Welsh independence within the European Union, focusing on social democracy and securing more funding and powers for Wales. In contrast, Reform UK, founded by Nigel Farage as the Brexit Party, campaigns on a platform of tax cuts, reduced public spending, and stringent immigration controls.

Relevance for Kenya and East Africa

While a Welsh by-election may seem distant, the dynamics at play in Caerphilly offer a compelling case study for Kenya's multifaceted political environment.

• By-Elections as Political Barometers: Much like in Kenya, this by-election served as a crucial test of the national mood. The collapse of the Labour vote is being interpreted as a significant rebuke of the party's performance in government, both in Wales and Westminster. Similarly, Kenyan by-elections are often viewed as referendums on the ruling administration and a chance for opposition parties to gauge their strength and test campaign strategies ahead of general elections.
• The Power of Tactical Voting: The Caerphilly result is a clear demonstration of tactical voting's power to shape outcomes under a first-past-the-post system. In Kenya's diverse political landscape, where elections can be tightly contested, the concept of voters crossing party or coalition lines to block a candidate perceived as a greater threat is a recurring theme, particularly in gubernatorial and parliamentary races. This result underscores how a united front, even if informal, can overcome perceived frontrunners.
• Regionalism and Devolution: Plaid Cymru's victory is rooted in its strong Welsh identity and its campaign for a "fair deal" for the region. This mirrors the powerful role of regional and ethnic identity in Kenyan politics. The principles of devolution in Kenya were designed to address historical grievances of marginalisation, and political parties often build their support bases around regional concerns. Plaid Cymru's success highlights how a strong, region-focused message can triumph over national political waves.
• Countering Populist Movements: The rise of Reform UK in Wales reflects a global trend of populist parties challenging the political establishment. The coordinated tactical vote against them in Caerphilly provides a potential model for how mainstream and other political actors can counter such movements at the ballot box. As Kenya navigates its own economic and social pressures, the lessons from this Welsh contest in mobilising a broad base to defeat a polarising force are particularly pertinent.

In his victory speech, Mr. Whittle paid tribute to his predecessor, Hefin David, and sent a message to the political establishments in Cardiff and Westminster, stating, "This is Caerphilly and Wales telling you that we want a better deal." The result leaves the Welsh Labour government in a more precarious minority position in the Senedd, making it harder to pass legislation and its budget. For observers in Kenya, it is a stark reminder that even century-long political dynasties are not immune to shifting voter allegiances and strategic electoral action.