Britain is better off than it was 14 years ago, Rishi Sunak has said, as he launched a combative defence of his party’s record in power with just four days to go until the election.

In what polls suggest will be his final Sunday morning interview as prime minister, Sunak defended his party’s achievements since 2010, saying the country’s recent economic problems were the result of the pandemic and the war in Ukraine.

He told the BBC’s Laura Kuenssberg: “[This] is a better place to live than it was in 2010. Of course, I understand that the last few years have been difficult for everyone – we had a once in a century pandemic, followed by a war in Ukraine that drove up everyone’s bills – and of course, that’s been difficult for everybody.”

He added: “It’s been difficult but we are now on the right track with the prospect of more tax cuts to come to give people more financial security and that’s the key choice for people at this election, building on the progress that we’ve made.”

Asked whether Britain had lost some of its international standing since Brexit, Sunak said: “People are queuing up to work with us because they respect what we do. I just completely reject that. It’s entirely wrong, this kind of declinist narrative that people have of the UK, I wholeheartedly reject that.”

Sunak’s words contrast with the relatively bleak picture painted by much of the economic data about what has happened to the UK since 2010.

Figures from the Institute for Fiscal Studies show growth has never recovered to its pre-2008 trend, leaving each person on average £10,900 worse off as a result. Real wages have shown almost no growth since 2010, while business investment is well below its pre-Brexit level.

In recent weeks there has been better economic news, with inflation falling to 2% and growth beginning to tick up once more. Sunak has sought to build his campaign around those early signs of a recovery, coupled with warnings about potential tax rises under a Labour government.

Kuenssberg confronted him with a series of messages from viewers that suggested, however, that his message had fallen flat with voters. One person asked: “Why isn’t anything working in this country?” and another, called Sheila, said: “Our biggest worry is not about tax. It’s about having the basics.”

Sunak replied: “Of course, it’s been very difficult when inflation rises to the highest level that we’ve seen in decades, when energy bills double because of the war in Ukraine, of course that has an impact on Sheila and everyone else, and that’s why I’m working so hard to deliver people financial security.”

Throughout the last five weeks, Labour has retained its 20-point poll lead, albeit with both main parties falling and Reform and the Liberal Democrats picking up ground. Sir John Curtice, professor of politics at Strathclyde University, said on Sunday: “Polls on average put the [Conservatives] on just 100 seats, while Labour could win a record 450.”

Sunak’s campaign has been beset by missteps, from his early rain-soaked election announcement, to his decision to leave the D-day commemorations early, to more recent revelations about betting by close aides on the date of the election.

He insisted on Sunday, however, that he was proud of the campaign he and his party have run. He said: “This campaign has shone a spotlight on the fact that a Labour government is going to raise everyone’s taxes and they’re not being straight with everyone about it, and I’m proud of that.”

The prime minister has largely enjoyed the full-throated backing of Conservative-leaning newspapers during that period. But on Sunday the Sunday Times became the first Murdoch-controlled publication to switch from the Conservatives to Labour, saying in a leader column: “We cannot go on as we are, and we believe it is now the right time for Labour to be entrusted with restoring competence to government.”

The Sun and the Times are expected to make their endorsements this week, in moves that could add crucial late momentum to the Labour campaign.