Changes to the “non-dom” regime will bring in only a quarter of the tax revenue estimated by official forecasts, according to the Centre for Economics and Business Research.

Even if nobody left the UK as a result of reforms for non-domiciled individuals, the changes would bring in about £2.5 billion in the first year, against a forecast by the Office for Budget Responsibility (OBR) of £10.3 billion.

The Centre for Economics and Business Research, an economics consultancy, said that the OBR’s estimates of the foreign income gains of those affected by the changes appeared to be too high, meaning the total tax accrued would probably be far less than it said.

The CEBR added that if a quarter of non-doms left the UK because of the reforms, the net gain to the Treasury would be zero.

In the October budget Rachel Reeves, the chancellor, abolished the “remittance basis” allowing non-doms to shield worldwide income from British tax, effective from April 6 this year.

The CEBR report said that if more than a quarter of non-domiciled taxpayers left the UK, “the Treasury would begin to make a loss”. If half left, the net losses to the Treasury in the first year of the scheme would increase to £2.4 billion, it estimated.

Non-doms liable for the old “remittance basis” regime had an average income tax bill 78 times higher than that of the median-income earner. Andrew Griffith, the shadow business secretary, said: “This independent research shows that once again the chancellor has got her sums badly wrong and does not understand business.”

People leaving the UK for brighter shores was “nothing short of disastrous for our economy”, Griffith added.

Modelling by the Adam Smith Institute, a think tank, has estimated that the tax change will lead to the loss of 44,000 jobs by 2030 and £111 billion of growth by 2035.

Charlie Sosna, head of private wealth and tax at the law firm Mishcon de Reya, said: “We saw a significant number of clients leave the UK for other jurisdictions — for example, Monaco, Italy, Dubai and Switzerland — last year, and we are working with more clients this year who are planning for their departure. I expect the figure could be much higher than 25 percent. I would anticipate the figure being closer to 40 percent.”

Registry filings show that Nassef Sawiris, Egypt’s richest person and the co-owner of Aston Villa, moved to Italy in April. Frédéric de Mévius, a member of one of the three founding families of the brewing company AB InBev, recently moved to Belgium.

A study by Oxford Economics showed that 60 per cent of tax advisers expected more than 40 per cent of their non-dom clients to leave within two years of the policy change.

There were about 74,000 non-dom taxpayers in the UK in the financial year ending 2023, down from 137,000 in the 2007-08 tax year. In 2015 there were 55,100 non-doms taxed on the remittance basis. This number fell until 2021, when it increased slightly to 37,800.

Sosna said that the loss of non-doms could affect the economy in less direct ways. “The behavioural response of the non-doms leads to a brain drain and loss of contributions ... For example, many non-UK domiciled individuals are significant donors to the arts.

The CEBR review was commissioned by Andrew Barclay, the founder of Yopa, an online estate agent.

The OBR was asked for comment.