“It’s entirely wrong, this kind of declinist narrative that people have of the UK. I wholeheartedly reject,” he said. “It [the UK] is a better place to live than it was in 2010.’’

After 14 years of Conservative-led governments, many voters blame the party for Britain’s cost-of-living crisis, long waiting lists for healthcare, high levels of immigration and the dislocations caused by Britain’s departure from the European Union.

Sunak, who became prime minister in October 2022, has tried to silence his critics by arguing that his policies have begun to solve those problems and warning that Starmer, the Labour leader, would raise taxes if his party wins the election.

Meanwhile Nigel Farage, leader of Britain’s right-wing Reform UK party, said his party was doing better than expected after a “tough” few days, as he addressed supporters at a rally on Sunday.

Farage, one of the country’s most recognisable and divisive politicians, has been a thorn in the side for Sunak’s Conservative Party as the rise in Reform’s popularity threatens to split the right-of-centre vote.

A poll on June 27 showed the opposition Labour Party far ahead on 42 per cent, trailed by the Conservatives on 20 per cent and Reform on 16 per cent.

Farage, 60, told a crowd of more than 4,500 people at the “Rally for Reform” event held at the National Exhibition Centre in Birmingham that the past few days have been “tough” but he was not downhearted.

“We’re doing much better out there than anybody in the media, in politics, even dares to imagine in their worst nightmares. We are doing well,” Farage told his supporters.

The challenges of the past few days have included Reform being at the centre of a racism row, when one of its supporters was recorded making a racial slur about Sunak.

Farage told Sky News on Sunday: “Anybody who has a racist point of view I don’t want to know”.

A Reform candidate for a constituency in northern England, Liam Booth-Isherwood, said separately on Sunday he was disowning the party, citing reports of widespread racism and sexism and the failure of the party’s leadership to address such issues, according to a statement on the BBC.

Reuters has approached Reform for comment.

Given the overlap with some Conservative policies, there has been speculation in the British media that Farage could seek to join forces with that party at some point in the future, but speaking to Sky News on Sunday, Farage ruled that out.

“I want nothing to do with them. They’re awful … they are ghastly,” he said.

Running to become a British lawmaker for the eighth time after his previous attempts all failed, Farage’s Reform is unlikely to take more than a handful of seats even if it wins a substantial share of the total vote, because of Britain’s first-past-the-post electoral system.

Additional reporting by Reuters