SIR Keir Starmer will be plunged into the danger zone if he loses this week’s by-election, Labour MPs warn.

Voters will go to the polls in , Manchester, this Thursday in a battle between , the and .

Britain's Prime Minister Keir Starmer attending a Q&A at a railway depot.Labour MPs have warned that Keir Starmer will be plunged into the danger zone if he loses this week’s by-electionCredit: AFP A man walking past a "Welcome to Gorton" sign with cars on a road to the right.Voters will go to the polls in Gorton and Denton, Manchester, this ThursdayCredit: PA Odds from six bookmakers for the Gorton and Denton by-election, showing odds for the Green, Reform, and Labour parties.

Labour MPs say losing the previously safe seat will fire the starting gun on leadership campaigns.

But they expect a bad set of local elections in May will spark the next move against

One said: “Clearly if we lose Gorton and Denton, Keir will be entering the danger zone. But May will galvanise MPs who will be worried about their own seats.”

Labour, Greens and Reform are fighting over a chunk of undecided voters in Gorton and Denton.

A bullish local Labour Party has thrown everything but the kitchen sink at candidate Councillor

More than 500 activists were due to flood the constituency this weekend following a stampede of Cabinet ministers.

An email, seen by The Sun on Sunday, from Labour’s General Secretary Hollie Ridley to campaigners said: “The data we’re seeing shows that this is going down to the wire between Labour and Reform. The Greens just aren’t in play.

“A third of anti-Reform undecideds are breaking to us so far — over double that are going to the Greens.

“But there’s a lot of undecideds we need to reach.”

Bookies favourite is the Green candidate, plumber Hannah Spencer.

Reform hope their can come up through the middle thanks to splits in the Left vote.