Boris Johnson said he has “absolutely no problem” with increasing national insurance for millions of workers in order to fund the NHS and social care.

The Prime Minister said the 1.25 percentage point rise is “unquestionably the right thing” and shows the Government is prepared to take the “big decisions” for the country.

Mr Johnson acknowledged that households are facing tough times as a result of rising inflation and soaring energy bills but insisted the extra funding is needed for the NHS.

The Government has promised to invest £39 billion in health and social care over the next three years as a result of the tax increase, which came into effect on Wednesday.

But, in a sign of concerns about the effect on household finances, Chancellor Rishi Sunak raised the threshold at which people start paying national insurance from July, which will limit the impact of the new levy.

Speaking at the New Queen Elizabeth II Hospital in Welwyn Garden City, Hertfordshire, Mr Johnson said: “What we are doing today is unquestionably the right thing for our country, it’s the right thing for the NHS.

“Because we’ve got, here in the UK, we’ve now got backlogs, waiting lists of six million people.

“Everybody across the country knows somebody who is waiting for cancer treatment or some sort of procedure that’s crucial for their health.

“We’ve got to give our doctors and our nurses the wherewithal, the funding, to deal with that.”

He added: “I’ve got absolutely no problem with it. We’ve got to do the difficult things.

“We’ve got to take the big decisions, the right decisions for this country.”

Funding the NHS is “the biggest priority for the country”, he said.

With rising energy bills one of the biggest contributors to the squeeze on household finances, Mr Johnson said there was a “limit to the amount of taxpayers’ money” that could be used to address a global problem.

Asked whether families should eat cheaper food, not replace clothes, turn down the thermostat or turn heating off entirely, the Prime Minister said: “People obviously are going to face choices that they are going to have to make.

“We in the Government will do everything that we can to help.”

The “most important thing” that could be done was to have a “strong, robust economy in which you have a high level of security in your employment”.

The health and social care levy will be used to reduce waiting times and deliver millions more scans, tests and operations.

The Government has also set an aim of reforming the way routine services are delivered so the NHS is fit for the future.

Health Secretary Sajid Javid said it would be “morally wrong” to let “our children pay for our healthcare and our adult social care” by funding investment through increased borrowing.

He told BBC Breakfast: “The choice for us as a country is we either put that money in ourselves now, and if we don’t do it ourselves, we will have to borrow it. And that is mortgaging the future of our children and our grandchildren.”

The Cabinet minister could not say when NHS waiting lists will start falling, suggesting no government can control NHS demand.

“We estimate some 11 million people stayed away from the NHS during the height of the pandemic. I think we can all understand why that happened,” he said.

“I want those people to come back. I want them to know that the NHS is there, that it’s open for them. I want them to be seen.

“What I don’t know, no-one knows, is what proportion of those people will come back. Is it 50%? Is it 70% or 30%? That is why it’s very hard to put a number on where the waiting list goes. It is already at six million and it will go higher before it starts to come down.”

But Labour leader Sir Keir Starmer told ITV’s Good Morning Britain: “The sad reality is that a lot of the money that is gathered through this tax increase today in the end is going to be filling a black hole left by the incompetence of the Government on finance.”

Liberal Democrat leader Sir Ed Davey said the rise in national insurance “puts all the burden on working people”.

He told BBC Breakfast: “It doesn’t tax the unearned income of very wealthy people. It doesn’t tax the income of landlords. It puts all the burden on working people – that is wrong.

“Yes, we need more money for the NHS and social care. The Conservatives starved it of money and one reason why the pandemic was so difficult was that the Tories had underfunded the NHS.

“The problem we have at the moment is that the Conservatives are not only taking an unfair approach to funding the NHS, but they are putting this tax rise up just at the wrong moment.”