Sir Keir Starmer is scrambling to save his floundering by-election campaign as the hard-Left Green Party threatens to snatch victory in Gorton and Denton. The embattled Prime Minister, now rated the worst in living memory by pollsters, has ordered Labour MPs to flood the seat and even given them permission to skip Prime Minister’s Questions.

An Opinium poll puts Green candidate Hannah Spencer on 30%, with Labour and Reform tied on 28%. Ms Spencer, 34, could make history tomorrow by becoming the first Green MP elected in a by-election, delivering a humiliating blow to Labour in what has been a traditional stronghold for the governing party.

The shock result would come as Sir Keir reels from the Lord Mandelson scandal, with his former US Ambassador under police investigation for misconduct in public office. The peer was arrested and questioned by officers this week, plunging Downing Street into crisis just as voters prepare to head to the polls.

Reform UK’s Matt Goodwin has branded the vote a “referendum on Sir Keir Starmer” and told the Daily Express the PM would be forced to resign if Labour loses the seat. Ms Spencer has also said Sir Keir’s time would be up should Labour candidate Angeliki Stogia lose to her opponents.

The by-election has been a headache for Sir Keir from the outset. He sensationally blocked Manchester Mayor Andy Burnham from standing for the seat, claiming a mayoral election to replace him would cost too much. Critics said Sir Keir feared Mr Burnham, a popular figure in the region, would challenge his leadership from the Commons benches if he secured the seat.

The decision sparked fury among local Labour members and MPs, with many viewing it as proof Sir Keir was putting his own survival above the party’s electoral prospects. Labour MPs and ministers will flood the seat in the final 48 hours as the party desperately tries to win back voters tempted by the Greens and Reform.

Sir Keir himself visited Manchester on Monday but was kept away from voters amid fears his personal unpopularity would damage the campaign further. The Prime Minister’s ratings have plummeted in recent months, with the Mandelson scandal proving the final straw for many traditional Labour supporters.

Ms Spencer, a local plumber, has campaigned in the area for years and previously stood for mayor of the wider Manchester region. Her local roots and working-class background have proved a stark contrast to Ms Stogia, a councillor originally from Greece who has lived in the UK for over 30 years, and Mr Goodwin, a TV Presenter who does not live in the area.

But the Greens have faced fierce scrutiny over their controversial policy platform, which includes legalising heroin, ending badger culling and taxing people for going on holiday abroad. They have also come under fire for producing adverts in Urdu and Bangala as they attempt to win over voters in the seat.

This morning the Conservative shadow minister Andrew Bowie branded the party “downright dangerous”, saying the Greens wanted to “undermine the interests of this country.” He called their policies “madness”, branding them “Marxists painted green” with “no comprehension of how they would actually pay” for their radical agenda, which includes open borders.

Ms Spencer told the Daily Express earlier this month she would push for heroin legalisation if elected. She argued it would be safer for users if they were given access to the narcotic in a controlled environment that could also ensure health checks and medical supervision.

The Green Party has also come under fire for what critics describe as “sectarian politics” after distributing campaign leaflets in foreign languages. Ms Spencer was even criticised for driving a diesel car rather than an electric vehicle, undermining her party’s environmental credentials.

Despite the attacks, polling suggests Ms Spencer has built a formidable coalition of disaffected Labour voters, young progressives and Muslim voters concerned about Reform UK’s stance on immigration. The result will be seen as a critical test of Sir Keir’s leadership at a time when his authority is already under severe strain.

Polls close at 10pm tomorrow, with the result expected in the early hours of Friday morning