London | Rishi Sunak doesn't know whether he'll still be Britain's prime minister the day after next month's election. There's nothing unusual about that.

What is unusual is that he's been forced to deny rumours he could quit even before polling day, amid alarm inside the governing Conservative Party over Sunak's lackluster campaign.

Sunak gets a chance — maybe one of his last — to change the narrative on Tuesday when he releases the Conservatives' manifesto, a handbook of policies that forms each UK party's blueprint for power.

Despite gloomy polls and bruising headlines, Sunak insists the election is not a “foregone conclusion” and says resigning has not crossed his mind.

“People are going to say what they're going to say,” he told reporters on Monday. “The reality is I'm not going to stop going, I'm not going to stop fighting for people's votes, I'm not going to stop fighting for the future of our country.”

The Conservative manifesto is likely to include promised cuts to personal taxes, a chance for Sunak to repeat his claim that a government led by Labour's Keir Starmer would raise taxes while a Conservative one would lower them. The Labour Party points out that the tax burden has risen to its highest level in decades during 14 years of Tory rule.

On July 4 British voters will elect lawmakers to fill all 650 seats in the House of Commons, and the leader of the party that can command a majority — either alone or in coalition — will become prime minister.

Sunak's surprise decision to call a summer election — several months earlier than most people expected, even those in his own party — was intended partly to catch the opposition unprepared.

But it's the Conservatives who have seemed off-balance from the moment Sunak stood outside 10 Downing St. in the rain on May 22 to announce the start of the campaign.

The Conservatives were already on the defensive after jettisoning two prime ministers without an election in quick succession in 2022: first Boris Johnson, felled by scandals, then Liz Truss, who rocked the economy with drastic tax-slashing plans and lasted just seven weeks in office.

The party's prospects worsened last week when populist firebrand Nigel Farage announced that he would run for Parliament at the helm of the right-wing party Reform UK, vowing to be a “bloody nuisance” to the established parties.

While Reform, with its anti-establishment and anti-immigration rhetoric, is aiming to attract disaffected voters from both Conservatives and Labour, it's likely to take more votes from Sunak's party.

“The intervention of Farage has made it even less likely that Rishi Sunak will remain in Downing Street than was already the case — minimal though those prospects were,” said John Curtice, professor of politics at the University of Strathclyde.

Sunak then flew home early from commemorations in France of the 80th anniversary of D-Day so he could resume campaigning. The photos of centenarian World War II veterans and an array of world leaders including US President Joe Biden attending the solemn ceremony on Omaha Beach without him were a publicity nightmare.

Sunak quickly realised his error and apologised.

Paul Goodman, a former Conservative lawmaker who is now a member of the House of Lords, said the irony is that apart from the D-Day gaffe, “the Conservatives have run a perfectly decent, conventional campaign,” but have little to show for it.

“They've launched lots of policies, they've had some hits on Labour,” he said. “Rishi Sunak actually did pretty well in the debate (against Starmer) last week. … All of this appears to have made no difference at all.” Labour, eyeing a return to power after 14 years in opposition, is running a cautious campaign centred on the single word “change.” Starmer's core message — which dismays some in his left-of-centre party — is that he has transformed Labour from its high-taxing, big-spending days into a party of the stable centre.

“Politics is a relative business,” said Philip Cowley, professor of politics at Queen Mary University of London. “You don't have to be liked, you just have to be more popular than the other guy. And that's what the Labour Party by and large are managing to pull off.”

While opinion polls giving Labour a double-digit lead may change, Curtice, one of Britain's leading polling experts, said Sunak was facing a steep mountain to climb even before he called the election.

“Arguably the Tories' days were numbered the moment that Liz Truss fouled up,” he said. “Because no government that has presided over a market crisis has survived at the ballot box.”