Labour is mounting a frantic final by-election effort with warnings defeat could spell the end for Keir Starmer.
The contest in Gorton & Denton is entering its last few days with the Greens seemingly trying to 'weaponise' the Gaza issue.
Labour has been hoping to paint Thursday's vote - in a traditional stronghold seat - as a straight fight with Reform, which has been riding high in national polls.
But even the more optimistic activists believe the outcome is on a knife-edge, with the very limited polling so far suggesting a three-way split. Constituency-level surveys are notoriously difficult to conduct.
Deputy leader Lucy Powell pleaded with residents in the Manchester constituency not to let Nigel Farage's party in by 'turning to the Greens'.
Writing in the Sunday Mirror, she said the Greens were 'peddling misinformation' about being the only viable alternative to Reform.
Labour general secretary Hollie Ridley told an all-staff call on Friday that Zack Polanski's party is 'clearly high on the Class A drugs they want to legalise if they think they're in this race'.
Green campaign literature includes Urdu translations of messages including this one insisting it is the only party that can beat Reform.
Reform candidate Matt Goodwin has branded the by-election a referendum on Sir Keir's leadership, as he struggles to cling on in No10.
However, Jeremy Corbyn has been in a seat offering his support to the Greens, after Your Party decided against standing a candidate.
'There is only one way we will defeat Reform: together. That's why I'm backing the Greens in the Gorton and Denton by-election,' he said.
The Greens have been trying to mobilise the significant Muslim vote in the seat.
Campaign fliers written in English and Urdu show candidate Hannah Spencer wearing a keffiyeh with the message 'punish Labour for Gaza'.
Ms Spencer told the Middle East Eye: 'People are really angry about how Labour failed to call it a genocide or to bring any measures against the Israeli government.'
Reform candidate Matt Goodwin has branded the by-election a referendum on Sir Keir's leadership, as he struggles to cling on in No10.
Losing the battle could spark a fresh bout of speculation about the premier's future, with grim local elections looming in May.
Jeremy Corbyn has been in a seat offering his support to the Greens, after Your Party decided against standing a candidate.
One Labour veteran told the Daily Mail it would come down to who could get their vote out most effectively.
'I think most voters aren't sure of any of the parties,' the frontbencher said.
'Just look at the polls. Everyone seems to be around 20 per cent with Reform mid 20s...
'It's not very convincing for anyone at the minute. Five parties in a two-party system.'
A Green Party spokesman told the Sunday Telegraph: 'Not all voters speak English as their first language so of course Greens wish to be inclusive. Our approach has been praised by locals who love their diverse community.
'Greens have been outspoken about the Labour Government's foreign policy failure over Gaza and it is well known that many voters wish to send a message to Labour at this by-election for very many reasons.'