Caerphilly By-Election: Reform 2/5 favourites with Plaid Cymru second and Labour set for ballot box misery

• Reform favourites to end Labour dominance in Caerphilly

• Market says Plaid Cymru will push Labour into third 

• By-election result will give clues to parties' standings nationally

• Get the latest Betfair Exchange odds for Caerphilly by-election

Caerphilly by-election looks to be Reform v Plaid Cymru

Rumours of Labour's demise in Welsh politics have been circulating for some time and we will soon see evidence of that when voters go to the ballot box in the Caerphilly by-election.

The odds on the Betfair Exchange do not make for good reading.

Labour are a distant third to win the election, which takes place on Thursday October 23, at odds of nearly 17.016/1. 

That is despite winning the seat in every Westminster and Senedd election in the last 100 years. South Wales has been a stronghold for Labour in the 21st-century and losing next week's by-election would indicate their waning popularity in Wales and the UK more widely. 

Reform aim to win first Senedd seat in Caerphilly

Labour are currently the largest party in the Senedd, with 30 of the 60 seats. They are already reliant on other parties to help them pass legislation and losing Caerphilly would make party leader and first minister Eluned Morgan's job more difficult. 

Reform have said they will throw everything at winning the by-election. The party, which has five MPs in the Westminster House of Commons, has never won a seat in the Senedd.

Winning a first seat there would be a further indication that they are on course to challenge at the next UK general election. 

Nigel Farage is 4.84/1 favourite to be the UK's next prime minister while Reform are 1.9210/11 to win the most seats with Labour 3.412/5. 

Reform win would rock General Election and Senedd betting markets

The UK general election isn't scheduled to take place until 2029 - although the prime minister has the option to call it before then - and, in the meantime, there will be Welsh elections next year.

A victory for Reform would send a message that they can make inroads at the Senedd in 2026 and shake up its make-up in the same way they are hoping to do in Westminster. 

Next week's by-election is not a foregone conclusion, however, and Plaid Cymru will believe that, over the next nine days, they can wage a campaign that will deny Reform.

Plaid are telling voters in Caerphilly to abandon Labour, arguing that only they can stop Farage's party from claiming a first Senedd seat. It is a message that could yet resonate with enough voters to keep Reform out of Wales.

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