Boris Johnson has said the UK is “not necessarily” heading for a recession after his chancellor announced a £15bn package to help people deal with rising energy bills and inflation.

Despite experts warning of trouble ahead for the economy and the government bringing in emergency measures to help out struggling households, the prime minister sounded an upbeat note about Britain’s financial prospects in an interview with Bloomberg TV.

“There are ways forward for the UK that are incredibly exciting,” he said. “If we make sure that we have a proactive approach to talent from abroad – we want to control immigration but allow the talent that we need to come in – we fix our energy supply issues, we fix the issues in the UK labour market.

“One of the incredible things about the economy right now is that unemployment is at its lowest level since I was two years old.”

He acknowledged there would be a “difficult period” ahead but said he was confident energy prices would start coming down.

Asked if the UK was heading for a recession, he answered: “Not necessarily at all.”

Johnson’s economic optimism has been wrong in the past when he gave an interview last year saying inflation fears were “unfounded”. It has since hit 9% and there are worries it could be in double digits by the end of the year.

Rishi Sunak, the chancellor, launched a package of measures on Thursday designed to tackle soaring fuel bills amid the cost of living crisis, but the measures have proved controversial with Conservatives MPs who would rather have seen tax cuts.

Speaking in a round of broadcast interviews on Friday, Sunak said he remained a “fiscal conservative”. He also did not rule out further emergency relief next year.

The package of relief was more ambitious than predicted but Sunak was quick to insist he had not changed his politics.

“First and foremost, I’m a fiscal conservative; I believe it’s incredibly important that I manage the country’s finances responsibly,” he said on Friday morning. “That means, after suffering the shock we did, to get our borrowing and debt levels back on a sustainable trajectory.”

Asked if he would be prepared to introduce a further emergency package in future, with fresh borrowing and taxes, he said: “People can judge me by how I’ve acted over the last couple of years.

“I’ve always been prepared to respond to the situation on the ground, what’s happening to the economy, what families are experiencing and making sure we’ve got policies in place to support them through that.

“In terms of ‘Is it one-off, what’s happening next year?’, I’d go back to what I said earlier. I do want people to be reassured and confident that we will get through this. We will be able to combat and reduce inflation, we have the tools at our disposal and after time it will come down.”

Commenting on the fact that every household across the UK would receive a £400 grant to help cope with the rapidly rising energy costs, including wealthy individuals such as himself, the chancellor said he would be donating his to charity and encouraged others who did not need it to do the same.

He told Sky News: “I am sure, like me, you can also give that money to charity if you don’t need it.”

He said second homes would account for only 1-2% of payments, adding that he had not wanted to use council tax to give the money to households because of the risk that it penalised families in larger homes who were cash poor.

Sunak denied the shadow chancellor Rachel Reeves’ suggestion that he had implemented a Labour policy, telling BBC Radio 4’s Today programme: “I don’t think that’s fair.”

Labour proposed a windfall tax on energy companies five months ago.

He also denied the package was brought forward to generate positive headlines after Sue Gray’s report exposed a culture of “bacchanalian” parties in Downing Street.

Despite a turbulent few weeks, where he has been fined for breaching Covid rules and his family’s finances have come under scrutiny, Sunak said he was not planning to resign.

He told the BBC: “No. I am fully committed to helping get the country through what are some challenging months ahead and build a brighter future for the people that I’m very privileged to represent.

“And, as you saw yesterday, I have the same energy and verve I’ve always had for this job and I’ll keep at it.”