According to data seen by the private client law firm Bircham Dyson Bell, the number of UK non-doms has fallen from 139,000 to 123,000 – or 11.5 per cent – following the introduction of the £30,000 levy.

But it is not the levy alone which has acted to drive international investors away from the UK, says private wealth partner James Johnston, but rather a “series of highly complex and confusing changes to the way in which their international wealth might be taxed if they stayed here”. One particular area of confusion is the criteria individuals must satisfy to qualify for non-dom status.

Going back a few years, the then Labour government gave the impression that it was willing to “move the goalposts very far very quickly," says Johnston, and the result of these changes has been the erosion of the international community’s confidence in the UK as a place to live and invest.

What is needed to rectify this is clarity, he says, such as clear rules on what level of presence in the UK constitutes tax residence, and he urges the government to carefully weigh the potential loss to the economy in turning away investors and employers from overseas rather than incentivising them to come to the UK.

“Other countries are only too happy to offer incentives to attract foreign investment – for example Switzerland, France and Spain (all of which are non-tax haven jurisdictions) have all done so,” Johnston said.

“It is to be hoped that the Coalition government will learn from the mistakes of its predecessor by refraining from introducing change in this area of the tax legislation without careful consultation and dialogue. From this point of view, the initial signs are encouraging.”