According to law firm McGrigors, which obtained the figure under the Freedom of Information Act, the number represented 11.5% of the total UK non-dom population that year.
One report said the decline marked the first time in five years the number of non-doms leaving the UK exceeded those arriving.
Some believe the decrease from 139,000 non-doms in the tax year 2007-08 to 123,000 in the year 2008-09 will cumulatively lead to lost tax revenues far in excess of the £162m earned so far from the £30,000 charge, which was introduced in 2008.
The fee is levied on resident non-domiciled individuals – many, though far from all, of them foreign city workers and business people – who want to live in the UK but only pay taxes on local income and gains and any assets they bring into the country.
It was brought in by the then Labour government in response to the financial crisis and a perception that wealthy foreigners were effectively treating the UK as a tax haven because – unlike full UK taxpayers – they were not taxed on their worldwide income and gains.
‘Brain drain’
However, there were claims at the time the fee may lead to a ‘brain-drain’ as many talented foreign workers opted to leave the UK rather than pay it – the alternative to which if they remain in the UK is to be taxed on a worldwide basis.
Phil Berwick, director at McGrigors, said: “We can only hope that this outflow does not continue.
“A lot of the most valuable non-domiciles in terms of spending power are incredibly mobile – they can live anywhere. Unfortunately many of these high net worths will have taken the £30,000 annual levy as a message that the UK is not such a welcoming home to them.”
He added that many non-doms were businesspeople who represented genuine value to the UK economy in terms of expertise, job creation and linked tax revenues.
“The spending power that has been lost to the UK economy is surely going to be far in excess of the income gained by the Treasury,” said Berwick.