Plaid's emphatic election victory a warning to Labour and Reform

IF ANY seat has a claim to be part of Labour's electoral heartland, it is Caerphilly.

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Labour's electoral dominance there reaches all the way back to the creation of the constituency in the 1918 UK general election, when Alfred Onions became the first of many Caerphilly Labour MPs.

This pattern has heretofore been replicated in Wales' devolved elections, where the seat has always returned a Labour member.

This gives a sense of the blow dealt to Welsh Labour in the Senedd by-election held there on October 23. Plaid Cymru candidate Lindsay Whittle, a man who has stood and failed to win in the constituency in 10 Westminster elections going back to 1983, won the Caerphilly Senedd seat with 15,960 votes to Labour's 3,713.

In one sense, this was a surprise result. Reform's Llŷr Powell was the bookies' favourite to take the seat and Whittle's vote share was well above what pundits and analysts had anticipated. Labour's third-place finish was widely predicted, but ultimately it undershot even the dismal expectations set. Plaid Cymru's 11.4% margin of victory over Reform was greater than Labour's entire vote share.

Typically, by-elections are difficult to project forward onto nationwide votes so it's not wise to predict future Senedd or general elections from these results. By-elections often play out amid emotive and idiosyncratic circumstances, such as a member resigning in disgrace or an unfortunate passing. With the death of Hefin David, this contest falls into the latter. By-elections are also often difficult for parties in government, as they can engender protest-vote dynamics. Voters feel able to give governing parties a kicking with relatively few political consequences.

This particular by-election is particularly unrepresentative of next year's Senedd election, because the single-seat tier of the Welsh electoral system has been removed for future Senedd votes. This means that tactical voting incentives won't be anywhere near as pronounced come next May's Senedd election.