LONDON — He is the U.K.’s most unpopular leader on record — more disliked, polls say, than even Liz Truss, the woman famously outlasted by a lettuce.

Little over a year after winning a historic landslide victory, British Prime Minister Keir Starmer faces what could be a make-or-break moment as he fights for his political future.

The embattled leader is set to tell his restive Labour Party that it is in a “fight for the soul of our country,” in an address Tuesday to its annual conference in Liverpool.

Starmer, 63, faces threats from all sides.

The Reform U.K. party led by Nigel Farage, a staunch ally and friend of President Donald Trump, is leading the polls. He has capitalized on discontent over the cost-of-living that has seen a rise in concern over immigration.

This is a familiar story across Europe, where mainstream centrists such as France’s Emmanuel Macron and Germany’s Friedrich Merz are being out-polled by nationalists and populists on the hard right.

Starmer’s attempted fightback has been to reject Farage — who he called “racist” this week — but also to deploy tougher talk on immigration himself.

He is set to tell the party in Liverpool that it must make “decisions that will not always be comfortable for our party. Yet at the end of this hard road there will be a new country, a fairer country, a land of dignity and respect,” according to a partial transcript released by the party ahead of time.

Starmer “needs to stamp his authority on the party and show he has a political story to tell that they can rally round,” according to Anand Menon, director of the U.K. in a Changing Europe think tank and a professor at King’s College London.

Not only has this strategy so far failed to shift Starmer’s dismal polling, it has also triggered dismay from Labour’s traditional left-of-center support base. They accuse him of abandoning Labour’s foundational liberal values.

“I don’t think he turns it around by leaning into Reform party rhetoric, which presents migrants and asylum seekers as the fundamental problem in Britain — they’re not,” said Scott Lucas, a politics professor at University College Dublin. “Britain’s fundamental problem is economic,” Lucas told NBC News. And so the question for Starmer is: “Can you return to Labor’s focus on public services, on competence and on finding a way forward which relies more on consensus rather than division?” he added.

NBC News has reached out to the Labour Party for comment on Starmer’s negative polling and the criticism of his leadership.

The world’s 6th largest economy is suffering from years of sluggish growth and stubborn inflation that’s forecast to be the highest this year among the G-7, a club of Western nations that includes the United States and Canada.

As in the U.S., that’s driven up prices for everyday goods, but real wages in Britain have stagnated since the global financial crisis of 2008. Subsequent budget cuts have left public services such as the National Heath Service crumbling in the face of rising demand.

During last year’s election, Starmer promised the British public that he would not raise taxes on “working people” — including income tax. But economic headwinds have fueled speculation that he may be forced into a U-turn during November’s annual budget. Starmer has already been forced into humiliating climb-downs on pensioners’ winter fuel payments and welfare reform.

He has also announced the introduction of digital ID cards — an attempt to clamp down on people working illegally that has been criticized by civil liberties groups — as well as formal recognition of Palestinian statehood, which has caused friction with Trump and whose critics say is too little, too late.

Though Starmer is technically safe until 2029, the scheduled date of the next election, he could come under threat before then if his party decides his leadership has become too toxic. The Labour Party conference this week has been awash with rumors that Andy Burnham, the mayor of Manchester often described in British media as “the King of the North,” could mount a leadership challenge.

Burnham has cooled that talk but even so, this has been a tumultuous year for Starmer’s own internal operation.

During the election, he ran on a platform of decency and abiding by the rules, an antithesis to the scandal-plagued ruling Conservative Party.

That narrative has been weakened by a series of ministerial resignations, culminating in that of Starmer’s own deputy, Angela Rayner, after it was revealed she underpaid property taxes.

Starmer has also carried out a radical overhaul of his internal communications team in a bid to reverse his downward fortunes. On Tuesday, his press office said his speech would mark a “fork in the road” for the country.

“The question is, fork in the road moment for what?” said Lucas at University College Dublin. “There’s a fork in the road moment for Labour, at least in terms of where are we going to go with the question of immigration and a proper asylum system,” he said. “Can Starmer show that he still has authority within the party when you’ve got a rising hard right?”