A London-based billionaire non-dom left the UK for good on the day that the chancellor, Jeremy Hunt, announced the scrapping of the 225-year-old tax scheme in the spring budget, his tax adviser has revealed.

“We did have one billionaire client who literally on the day of the budget, 6 March, got on his private jet with his wife, with his children, with the private tutor, and flew to one of his other 17 houses in the world – and said ‘I’m not coming back’,” said John Barnett, a partner at the law firm Burges Salmon, which specialises in advising the super-rich on how to legally reduce their tax bills.

Barnett and other tax advisers to the very wealthy, say dozens of their non-domicile clients have already left the country to avoid being subjected to UK taxes on their overseas income, after Hunt announced the abolition of the regime from April 2025. They expect hundreds more to leave for other countries such as Italy, Spain, France and Malta that have special tax incentives designed to attract the very rich and very mobile.

“If you’re in the billionaire class, you’ve already got the houses elsewhere, you’ve got the private tutor for your children, you’ve got the private jet – you can leave straight away,” Barnett told a conference celebrating the super-rich at the Savoy hotel in central London. “I think for most other groups below that, it’s not an immediate decision. You’ve got children in school … spouse issues to contend with, you’ve got a business to sell, you’ve got a house to buy – it’s a two to three-year decision to move.”

Barnett said he expected that a lot of the non-doms would go abroad to avoid the increased tax burden, but would still spend a lot of time in the UK, particularly for the popular social and sporting events over the summer.

“A lot of these people will make themselves non-resident … but will probably still be able to spend three to four months here in the summer [before the Treasury would consider someone a permanent resident]. So you can still go to Wimbledon, go to the Chelsea flower show, all those sorts of usual things.”

There were 68,800 non-doms in the UK in 2021-22, according to the latest available HM Revenue and Customs data.

Camilla Wallace, a senior partner and tax adviser at the London law firm Wedlake Bell, said many of her non-dom clients were also looking to leave the UK as quickly as possible. She said a “very lovely Brazilian client, who has bought a very expensive house in central London and is now spending millions doing it up” had asked her this week where he should go.

“I said to him that it really depends on what you like. So some people like mountains and skiing and some people like glitzy stuff, so Monaco and Dubai are great for that. Others like islands and sailing,” she said, speaking last week at the Spear’s 500 wealth management conference. “So you look at the human element of the move and then you check out what tax breaks they [other countries] are offering, and some places in Europe have been doing exceptionally well.”

Barnett said many of his clients were keen to move to Italy, which introduced a scheme through which rich people could pay a “flat tax” of just €100,000 (£85,000), no matter how much money they earned.

France, Greece, Cyprus, Malta, Portugal and Spain have similar schemes designed to attract the wealthy and internationally mobile elite. Spain’s expatriates tax regime is nicknamed the Beckham law after David Beckham, who became one of the first people to use it when he was playing for Real Madrid in the mid-noughties.

“There’s a new one [expatriate tax deal] every week – just keeping on top of it is difficult,” Barnett said. To which Wallace added: “We’re shutting down, and everyone else is opening up.”

Julia Hope, the chief executive of Innovate LSO Solutions, a company that encourages people to relocate to Barbados, said: “I’m sure we may well have a billionaire or two who can jump on their plane and just come across and spend some time at [the luxury resort] Sandy Lane or somewhere [else] exclusive.”

The multi-millionaire non-dom entrepreneur Bassim Haidar told the Guardian earlier this month that he was leaving the UK as soon as possible because the scrapping of the regime “is going to cost me millions and millions of dollars and pounds every year in taxes on money that I’ve actually made abroad and businesses that I’ve built abroad”.