Britain is set to lose a fifth of its millionaires under this Labour government, it was claimed today – as economists called for wealthy emigres to pay an ‘exit tax’. Government tax raids means that the 4.55 per cent of British residents with over $1million in assets will fall to just 3.62 per cent by 2028, according to the Adam Smith Institute (ASI). Research from the economics think tank suggested millionaires are leaving the UK due to increased day-to-day taxation, frozen inheritance tax thresholds and a potential increase in capital gains taxes.Wealthy Brits also fear the abolition of the non-dom regime – despite the crackdown predicted to fail in yielding any extra tax income.Today, a separate think-tank called for leavers to face a tax on their assets when they leave the UK.   Policies set to be announced by Chancellor Rachel Reeves are being blamed for an exodus of millionaires from the UK. Currently the UK does not charge capital gains tax (CGT) on rich entrepreneurs and investors who leave the country for more than five years Pimlico Plumbers founder Charlie Mullins is one of the most high profile figures to announce plans to leave the UKAnalysts at the Centre for the Analysis of Taxation (CenTax) argued that the lack of a capital gains charge for fleeing businesspeople provided an incentive for the wealthy to move abroad in order to cut their tax bill. Currently the UK does not charge CGT on rich entrepreneurs and investors who leave the country for more than five years.As a result, three-quarters of leavers move to countries where they can sell their firms or investments without paying any tax on their gains, a report found. Pimlico Plumbers founder Charlie Mullins is one of the most high profile figures to announce plans to leave the UK, with the entrepreneur saying he will sell his £12m penthouse and leave the country to avoid a Labour tax raid on his £145m fortune. CenTax argued that the UK’s lack of a CGT charge for wealthy leavers made it an ‘international outlier’ and suggested a charge could raise £500m.   Arun Advani, director of CenTax and Associate Professor at University of Warwick, said: ‘If politicians are worried about emigration, they could follow Australia, Canada and many other countries by taxing the gains of people who leave. ‘It’s a policy choice to let them emigrate tax free.’Andy Summers, director of CenTax and Associate Professor at the London School of Economics (LSE), said: ‘Charging CGT on people who leave the UK is not about punishing them for leaving. It’s simply saying: ”you need to pay your bill on the way out”. ‘Most of the UK’s international peers already do this, and there is no reason why the UK couldn’t as well.’However, Nigel Green of financial advisory firm deVere Group argued calls for an exit tax were ‘fundamentally flawed’ .’The proponents of the exit tax are missing the point,’ he said. ‘At a time when economic growth needs a boost, and international competition for talent and capital is at an all-time high, this tax would do more harm than good.’The problem that academics and policy advocates fail to acknowledge is that policies like this discourage people from coming to the UK in the first place.’Worse still, it sends a negative message to the global investment community that the UK is hostile to wealth creators and innovators. It’s, therefore, fundamentally flawed.’The UK is only one of three major nations set to reduce in individual millionaires over the next few years, along with the Netherlands and Saudi Arabia. Others – such as Taiwan, Japan and South Korea – will see their own numbers rise by a third or more.The Chancellor has now been told to lay out a more business-friendly environment for wealth creators at this month’s Budget. She was warned against targeting the top one per cent of earners, who pay 29.1 per cent of all income tax.The ASI’s Millionaire Tracker suggests that the UK is set to lose 9,500 ‘liquid millionaires’ – wealthy individuals who hold over $1million in cash or investable assets – in 2024, meaning the UK’s total number will fall to 593,000. This is far below the figure in 2007, when the UK had 708,500 liquid millionaire residents. The ASI’s Millionaire Tracker suggests that the UK is set to lose 9,500 ‘liquid millionaires’ – wealthy individuals who hold over $1million in cash or investable assets (file photo) Chad West, a 33-year-old tech executive who previously worked for Revolut and is now vice president at another fintech, recently told MailOnline he is actively considering moving abroadFormer chancellor Nadhim Zahawi said: ‘The rate at which millionaires are leaving the UK is a vote of no confidence in both our current tax and regulatory regime, and anti-business and anti-prosperity measures that could be coming down the line.’These individuals are often entrepreneurs and business owners. Their exit won’t just reduce necessary funds for public services- it will decrease investment in the wider economy too.’I urge the Government to rule out anything in the Autumn Budget on October 30, that could drive them away even more. ‘They should instead be focusing on attracting more millionaires from across the world to make a home and set up shop in Britain. Abandoning anti-non-dom policies and abolishing or cutting anti-wealth taxes would be a vital first step.’It comes as a survey seen by the NEWSWALLA reveals that 24 per cent of taxpayers plan to move their residency abroad due to fears about this month’s budget.Polling from Cornerstone Tax and Yonder also shows that a third of Brits say changes in taxation are the main reason why they would leave the UK. A fifth plan to migrate in the near future due to proposed tax hikes, while 16 per cent agree that the deciding factor influencing their decision to leave is the Autumn Budget.Chad West, a 33-year-old tech executive who previously worked for Revolut and is now vice president at another fintech, recently told MailOnline he is actively considering moving abroad.’I think most execs in the tech industry are planning ahead for fear of the worst,’ said the Scotsman, who lives in London.’Many of us are already fed up with effectively paying 60% income tax rates (as we are taxed at 45% and lose our tax free allowance as well), and now the fear of capital gains tax increasing from 20% will send everyone packing. ‘I had my house valued last week and I’m chatting to my accountant the next. I’m already looking at more favourable tax systems and quality of life in Europe, starting with Italy.’Capital gains tax increasing would be the most damaging. It will seriously harm London’s ranking as Europe’s tech capital. Most tech companies allow remote work, so you’ll see a huge amount leave for tax and quality of life reasons.’Meanwhile, advisers to the UK’s richest households have told how their phones are ringing off the hook as their clients rush for the exit.In a stark warning they said that high-net-worth families are packing their bags in a bid to protect their hard-earned assets – and some have already made the move. Sir Keir Starmer’s ‘gloomy’ warnings about a painful budget have been blamed for putting off rich people from investing in Britain One tax adviser, who asked to remain anonymous, said: ‘I almost feel like I should contribute to the Labour Party because of what they’ve done for our business.’He added: ‘People will pay over the odds to live in their native country, but even the most loyal Brit will abandon ship if the environment becomes too hostile.’The UK is expected to see an unprecedented net loss of 9,500 millionaires in 2024, according to consultants Henley & Partners.Tax and citizenship advisers to some of the UK’s wealthiest families have seen a sharp increase in enquiries about moving abroad, to lower tax regimes, since Labour won the election.Favourite destinations include Italy, Dubai and Ireland. Peter Ferrigno, director of tax services at citizenship advisory firm Henley and Partners, told after the election how his firm had gone from receiving very few queries before the election to several a week since.’Judging by how busy we are, it is a concern for absolutely everyone,’ Mr Ferrigno said. ‘It is the difference between having enough money to retire or not having enough money to retire. [Clients feel it is] forcing their hand’.He added that an increase in Capital Gains Tax would be ‘the last straw… people who were prepared to pay 20 per cent are now considering leaving.’ It is ‘desperately, desperately sad’, he said.David Lesperance, the founder of tax and immigration advisory Lesperance and Partners, said enquiries about leaving the country doubled when it became clear that Labour would win the election in July.’Ever since Rachel Reeves started talking about a ‘fiscal black hole’, my wealthy UK non-dom and domiciled clients have been looking anxiously at the exit door,’ he said.’Sir Keir’s warnings about a ‘painful budget’ just reaffirms their concerns that major IHT and capital gains hits will be coming soon.’Mr Lesperance added: ‘The UK’s richest families are getting out while the getting is good.’You don’t wait until the fireman confirms your house is on fire before fleeing. Similarly, UK high net wealth individuals are not waiting for the Autumn budget to confirm that their fiscal house is about to be engulfed.’Jason Porter, of Blevins Franks, a financial advice firm specialising in cross-border wealth management, said the fear was now ‘palpable’ among millionaires, with growing numbers planning to relocate to shield their pension, property and investment assets.Mr Porter said he had received an influx of calls from wealthy families planning to relocate outside of the UK ahead of the autumn Budget. He said: ‘Families with large pensions or investments in shares are feeling under threat and interest in moving abroad is ramping up every month.’There were certainly a lot of people coming to us with big concerns over changes to capital gains tax, pension rules and inheritance tax, who are worried about what their situation could soon be like if they stayed.’In most cases they were people in the middle bracket of wealth, with a couple of million pounds, for whom it can take time to move their assets.’Are you a millionaire planning to leave the UK? Email rory.tingle@mailonline.co.uk