Almost half of the UK's largest non-domiciled group of taxpayers are preparing to leave the UK, claims Grant Thornton.
The financial adviser says expected changes to the nation's tax regime will force out 42% of non-domiciled 'high net-worth individuals' from India, Pakistan, Sri Lanka and Bangladesh.
A survey by Grant Thornton found that 84% of such taxpayers believe the planned £30,000 annual fee on the non-domiciled is not being set at a fair rate.
And 78% claim they don't have enough time to get their affairs in order in time to comply when the law changes on 6 April.
Only 34% of those surveyed said they would pay the £30K levy.
The mooted exodus within the UK's non-domiciled population has encouraged Grant Thornton to actively lobby the Government on a policy rethink through a formal submission.
The company's south-Asia group head, Anuj Chande, said it is not just a case of many individuals leaving the country. The forthcoming changes to tax status legislation is also discouraging many people from bringing their skills and entrepreneurial drive to the UK in the first place.
According to Mr Chande, key changes to the UK tax regime in April will have a huge impact on the fortunes of the non-domiciled community, and will need a major rethink should the Government be serious about keeping high net worth individuals in the UK long term.
'In the relentlessly competitive area of attracting talented individuals, the Government must appreciate that in 20 or 30 years it may be Singapore, Dubai or Zurich that will be home to a vast swathe of non-doms who could have been here,' Mr Chande added.