A by-election has been triggered following the resignation of Andrew Gwynne, who stepped down on health grounds, and it has the potential to send shockwaves through British politics.

The contest comes at a delicate moment for Keir Starmer, whose leadership of Labour is already under heavy scrutiny. With pressure building inside the party, there had been a growing movement urging Andy Burnham to mount a leadership challenge.

However, that route would have required Burnham to return to Westminster first, likely via this by-election, and to relinquish the Manchester mayoralty, a role he has consistently said he intends to serve out in full.

Those plans were effectively shut down when Labour’s National Executive Committee voted 8–1 against allowing Burnham to stand in Gorton and Denton.

The stated concern was that Burnham’s resignation as mayor could open the door for Reform UK to capture the Manchester mayoralty in what would be a costly and high-risk campaign for Labour.

By blocking Burnham’s candidacy, Labour may have created a different problem. The party now faces a serious threat from both Reform UK and a resurgent Green Party.

Early speculation that Green leader Zack Polanski would run proved unfounded, with Hannah Spencer instead selected. Reform UK have opted for Matt Goodwin, while Labour are re-standing Angeliki Stogia, who previously contested the 2024 general election in Chester South and Eddisbury.

Had Burnham been on the ballot, he would likely have headed the market.

Instead, Labour now find themselves outsiders, with their campaign complicated by the need to persuade voters that they, rather than the Greens, are the most credible barrier to a Reform victory.

Odds correct as of 10 February and subject to change.

Keir Starmer’s position as Labour leader and UK Prime Minister is facing increasing scrutiny following a difficult first year in office.

Labour swept aside the Conservatives at last July’s general election, returning to power for the first time since 2010 with a commanding majority.

However, the glow of that victory has faded quickly. Starmer has slipped sharply in the opinion polls, while Labour’s poor showing in the 2025 local elections has intensified questions over his long-term leadership.

Further pressure has come from the controversial appointment of Peter Mandelson as British Ambassador to the United States, a move that has divided opinion within the party and reignited internal tensions.

With the Gordon & Denton by-election looming, concern is growing inside Labour ranks.

Allies of the prime minister have already begun to push back publicly, bracing themselves for the possibility of a leadership challenge as the political temperature continues to rise.

Speculation around the next UK prime minister continues to gather pace, with Keir Starmer clinging to power.

For much of the market’s early movement, Wes Streeting had been installed as the favourite to succeed Starmer.

The health secretary has since drifted into second place after repeatedly playing down suggestions that he is manoeuvring for the top job, particularly amid renewed scrutiny of his past links to Peter Mandelson.

The momentum has instead swung behind Angela Rayner, who has emerged as the new market leader.

Reports suggest the Ashton-under-Lyne MP is prepared to mount a leadership challenge, and with no association to Mandelson, she is viewed by some as a cleaner break from Labour’s recent internal controversies.

Ed Miliband also features prominently in the betting. The energy secretary appears to enjoy broader public favour than during his previous stint as Labour leader, which ended in defeat at the 2015 general election against David Cameron.

All of this, of course, assumes that Starmer will not see out a full term. A snap general election remains a possibility, as does the prospect of Starmer remaining in post until 2029.

Further down the market, Nigel Farage remains a notable presence, with Reform UK continuing to poll strongly and keep his name in the conversation.

Keir Starmer’s future as Labour leader and UK Prime Minister is under growing scrutiny after a turbulent first year in Downing Street, with bookmakers now cutting odds on several rising figures inside the party.

Labour stormed back to power in last July’s General Election, securing a landslide victory and ending 14 years of Conservative rule. But the honeymoon period is already showing signs of strain.

Starmer’s personal ratings have slumped, Labour’s showing in the 2025 local elections was branded “dire” by party insiders, and criticism of the government’s budget statement has intensified questions over whether his leadership can withstand another year of political pressure.

Those close to Starmer have publicly defended him but behind the scenes, attention is shifting toward who could step in if the party decides a change is needed.

Streeting Installed as Clear Favourite

Wes Streeting, MP for Ilford North and the current Health Secretary, has been installed as the 7/2 favourite to become the next Labour leader, according to Skybet.

The outspoken frontline minister has found himself at the centre of Westminster gossip, with reports claiming he is being positioned as an alternative to Starmer.

Streeting dismissed the rumours with a tongue-in-cheek swipe at reality TV drama, saying:

“I think whoever’s been briefing this has been watching too much Celebrity Traitors — it’s about the worst attack on a faithful I’ve seen since Joe Marler was kicked out in the final!”

Despite the light-hearted response, his positioning in the betting markets reflects a notable shift in sentiment among political observers.

Burnham and Mahmood Close Behind

Trailing Streeting but still firmly in contention are two heavyweight figures with strong support bases inside the Labour movement:

Andy Burnham (7/1) – The Mayor of Greater Manchester remains a popular figure nationwide and has long been tipped as a potential future leader.

Shabana Mahmood (7/1) – The high profile Secretary of State is increasingly seen as one of the party’s sharpest communicators and a serious contender if the top job becomes available.

A Leadership Question Westminster Won’t Ignore

While Starmer remains firmly in post, political insiders admit he is entering a critical phase of his premiership.

With economic pressures biting, internal unrest growing, and the Conservatives beginning to regroup, senior Labour figures fear that a weakened Starmer could become a liability ahead of the next General Election cycle.

For now, the Prime Minister’s allies insist he will weather the storm but as bookmakers continue to shorten the odds on his potential successors, the question of “what comes next for Labour” is quickly becoming one of Westminster’s biggest talking points.