Prime Minister Boris Johnson‘s National Insurance increase has angered MPs on both sides of the House. One senior Tory MP has warned that the hike could undo the Conservative Party’s progress in former Labour heartland seats which turned blue in 2019. They told the Telegraph: “Next week shouldn’t worry or stress the Prime Minister or the whips. It’s what comes next that should.

“If the Labour Party is intelligent enough to brand this the Red Wall tax, because it hits the Red Wall harder than anywhere else, it will destroy us.”

Meanwhile, Sir Keir Starmer has been urged by Labour Party colleague Andy Burnham to back a wealth tax rise.

The Greater Manchester Mayor, who first proposed a levy when he was Health Secretary more than a decade ago, said he would introduce “a range of wealth taxes ‒ such as a higher rate of capital gains tax”.

Meanwhile, Sir Keir has come under pressure from parts of his own party to set out a plan for what Labour would do to address the social care issue.

One tax which the Labour leader has said should be “looked at” is capital gains tax.

However, an economist at the free-market Institute of Economic Affairs tells Express.co.uk that this could amount to a “triple taxation”.

Julian Jessop said: “The whole problem with inheritance tax and capital gains tax is a lot of them are running into the risk of being double or triple taxation.

“This is investments built up on the back of income that people have already paid tax on, so I think you should tax income not capital otherwise you discourage people from saving and investing.

“It’s another good example of how there isn’t an easy win here, if you want to get more money out of the economy it really needs to be based on income rather than wealth or anything else.”

He added: “I certainly think you should tax income at the same rate from whatever source, but the problem with aligning capital gains tax with income tax is this point about double taxation.

“Somebody has made their money on something, then they invest it in an asset, the company behind that share is paying taxes as well, if you then end up taxing the income from owning that share at the same rate as you do ordinary income, you end up actually taxing it at a higher rate because the company has already paid taxes on the profits used to generate that income.

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This is expected to rise because Mr Sunak froze the annual capital gains tax allowance at £12,300 until 2026 in his March Budget, dragging more people into the net.

As for inheritance tax, HMRC pocketed £5.4 billion in the 2020/2021 tax year, and will be looking for ways to raise yet more revenue from the levy.

UK businesses have warned that the UK’s economic recovery could be compromised by the decision to increase National Insurance bills.

Confederation of British Industry Director General Tony Danker has warned: “I am deeply worried the Government thinks that taxing business – perhaps more politically palatable – is without consequence to growth.

“It’s not. Raising business taxes too far has always been self-defeating as it stymies further investment.”

Jon Moulton, the founder of the private equity firm Better Capital and a former Conservative donor, said the Government was taking a “nanny state approach”.