Labour’s plans to increase Income Taxes for high earners so it can use the revenue to fund ambitious manifesto pledges are "a little on the optimistic side”, according to the Institute for Fiscal Studies (IFS).

At the launch of Labour’s general election manifesto on Tuesday, May 16, Jeremy Corbyn said the expensive pledges – which include scrapping tuition fees and raising the minimum wage to £10 an hour - will be funded by £48.6 billion of additional tax revenue.

Labour Manifesto promises

Labour is looking to raise the cash by hiking corporation tax, imposing a 45% income tax rate on people earning over £80,000 a year, and a 50% tax rate on people earning over £123,000.

However, the IFS said the new taxes may not raise any extra revenue as many high earners could decide to “make greater efforts to avoid or evade tax”.

In a report published on its website, the independent Think Tank said: "If no one changed their behaviour in response [to the tax increases], it would raise around £7 billion per year.

"But some of those affected would respond by reducing their taxable incomes, reducing the amount raised."

The report also states that the policy could work if Britain's affluent individuals pay the hiked taxes, but it could also "raise nothing".

Britain's top earners may decide to increase their contributions to private pensions to receive income tax relief, make more effort to avoid or evade the new taxes or decide to leave the country and live abroad, according to the IFS.

Will this impact the election results?

The Conservatives have also criticised the costing of Labour's new manifesto and said the sums "don't add up".

However, Mr Corbyn is confident about the calculations and at the official launch of the manifesto in Bradford, he said: "This is a manifesto for all generations. We are providing hope and genuine opportunity for everybody."

The manifesto also includes plans to re-nationalise Britain's railways and water companies, scrap zero-hour contracts, reverse disability benefit cuts, provide free school meals for all primary school children and free education for all adults, reduce the voting age to 16, build 100,000 affordable homes a year and renew the Trident nuclear weapon system.

Labour were boosted in the polls after Mr Corbyn outlined the party's ambitious manifesto, however, the Conservatives are still expected to retain their majority in the House of Commons after the general election on Thursday, June 8.