The number of sterling millionaires living in Britain has fallen to its lowest level since the global financial crisis, according to an inflation-adjusted estimate from the Adam Smith Institute.
Its Millionaire Tracker puts the total at 442,000, representing a 7% decline since 2024.
The think tank defines a millionaire as an adult British resident with individual net wealth of at least £1m across property, pensions and financial and other assets, measured in constant 2025 prices.
The figure is a modelled estimate drawing on Office for National Statistics data rather than an official register or direct count of wealthy residents.
PROPERTY VALUES
The Adam Smith Institute attributed the decline partly to falling real asset values, including weaker prices in London’s high-end housing market, alongside subdued household saving and the departure of some high-net-worth residents.
This means the reduction does not necessarily represent 7% of millionaires physically leaving Britain. Some households may have fallen below the threshold because inflation reduced the real value of their homes, investments or pensions.
Nevertheless, the findings will add to concerns among prime estate agents and developers about overseas and domestic wealth holders reconsidering their exposure to the UK.
The think tank linked the trend to taxation, the abolition of the previous non-domiciled regime and speculation about further wealth, inheritance and Capital Gains Tax changes.
TAX CONTRIBUTION
The Adam Smith Institute argues that losing wealthy residents could weaken investment, business creation and tax receipts.
Its release said the top 1% of earners contribute 29.1% of income tax, although the figure varies by tax year. HMRC currently projects that the top 1% of income taxpayers will account for approximately 26.6% of liabilities in 2025–26.
Mitchell Palmer, Economist at the Adam Smith Institute, says: “The decline in millionaires may be greeted as a success by some on the Left, but it should instead be viewed as a warning signal.
“Every millionaire that leaves means less capital for British businesses, fewer international connections and weaker entrepreneurial spirit in the economy.”
POLICY DEMANDS
The free-market think tank called for the abolition of inheritance tax, reductions or the phasing out of Capital Gains Tax and a review of the treatment of non-doms and high-net-worth individuals.
James Quarmby, Partner at law firm Stephenson Harwood, says: “Wealth and work are increasingly mobile, and it is very easy for individuals to move themselves, their money and their businesses elsewhere if sufficiently motivated to do so.
“It is important that the Government recognises this problem and strives to create a business-friendly environment to allow our private sector to grow and contribute to our tax base.”
