Britain now has fewer real-terms millionaires than at any point since 2008.
The Adam Smith Institute estimates there were around 442,000 sterling millionaires in Britain in 2025, down 7% in a single year.
Some will celebrate that.
They should not.
Britain does not become richer simply by having fewer rich people. Unless those lower down the wealth distribution are becoming better off, a shrinking millionaire population means less real private wealth in the country.
That matters for investment, businesses, jobs and tax revenues.
What Counts as a Millionaire?
The Adam Smith Institute defines a sterling millionaire as an adult UK resident with net wealth of at least £1 million.
That includes property, pensions, savings, investments and business assets, minus debts.
The threshold is measured in constant 2025 prices.
This matters because inflation can create millionaires on paper without making anyone genuinely richer. Someone whose assets rise from £950,000 to £1 million may cross the nominal threshold while losing purchasing power.
The tracker is therefore designed to measure real wealth, not the illusion created by rising prices.
The Lowest Level Since 2008
The Institute estimates that Britain had around 442,000 real-terms sterling millionaires in 2025.
That is:
• 7% lower than in 2024
• The lowest estimated level since 2008
• A reversal of the growth seen during much of the previous decade
The Institute attributes the decline to falling inflation-adjusted asset values, Britain’s low savings rate and the departure of wealthy individuals.
Higher interest rates and weaker asset growth have reduced the real value of some property, pensions and investments.
The report also argues that Labour’s changes to the non-dom regime, high taxation and the threat of further wealth taxes have made Britain less attractive to internationally mobile people.
What the Figures Can Tell Us
The figure of 442,000 is an estimate, not a census.
The Institute begins with total UK household wealth and uses a statistical model, calibrated against the Office for National Statistics Wealth and Assets Survey, to estimate how many people sit above the real £1 million threshold.
The model is better at identifying the direction of change than establishing a precise headcount.
It tells us that the estimated number of real-terms millionaires has fallen sharply.
It does not tell us exactly how much of that fall came from wealthy people leaving Britain.
Some will have dropped below the threshold because their homes, pensions or investments failed to keep pace with inflation.
Others may have taken on more debt.
Fewer people may be crossing upwards into millionaire status.
Some wealthy residents will also have left, while others may have decided not to move here.
The precise balance is uncertain.
The direction is not.
Britain is becoming less successful at creating, attracting and retaining real wealth.
Why This Matters to Everyone
The issue is not whether millionaires deserve special treatment.
It is whether Britain is retaining the people, businesses and capital that support the wider economy.
Britain’s public finances already depend heavily on a relatively small number of high earners. HM Revenue and Customs estimates that the top 1% of Income Tax payers contributed around 29% of Income Tax.
Millionaires and the top 1% are not exactly the same group, but there is considerable overlap between wealth, high earnings, business ownership, investment income and taxable gains.
When wealthy and economically active people leave, the Treasury can lose Income Tax, Capital Gains Tax, dividend tax, stamp duties, business taxes and future Inheritance Tax receipts.
Public spending does not automatically fall when taxpayers leave.
The burden can instead shift towards middle earners through frozen thresholds, higher employment taxes and broader tax rises.
Wealth also provides capital to businesses.
It is invested in companies, shares, pensions, commercial property and start-ups. That supports jobs, innovation and business expansion.
Not every millionaire is an entrepreneur.
But many business founders, investors and senior professionals bring experience, networks and access to capital.
When one of them leaves, Britain may lose more than one taxpayer. It can lose future investment, jobs, business activity and commercial connections.
Fewer Rich People Does Not Mean Less Poverty
A fall in the number of millionaires does not automatically improve the lives of people on low incomes.
It does not guarantee higher wages, more housebuilding, better public services, stronger productivity or lower poverty.
Nor does it prove that wealth has moved downwards.
There is a major difference between reducing inequality by making poorer households richer and reducing inequality by making wealthier households poorer.
Only the first represents genuine progress.
A fall in property or pension wealth after inflation is not redistribution.
It is simply wealth erosion.
Britain Cannot Tax Its Way to Prosperity
British politics spends far more time arguing about how to divide wealth than how to create it.
Each new tax may appear targeted in isolation, but together they affect whether successful and internationally mobile people choose to live, invest and build businesses here.
The abolition of the previous non-dom regime may raise more revenue from those who remain.
It may also encourage some to leave and deter others from arriving.
The final outcome depends on behaviour, not simply the tax rate written on paper.
Capital, talent and businesses are mobile.
Britain cannot assume they will stay regardless of how they are treated.
Conclusion
The fall in Britain’s millionaire population should not be dismissed as a problem only for the rich.
Some of the decline reflects property, pensions and investments failing to keep pace with inflation. Some may reflect weak savings. Some, according to the Adam Smith Institute, reflects wealthy people leaving or choosing not to come here.
The precise balance is uncertain.
The warning is not.
A country that loses investors, entrepreneurs and highly mobile taxpayers risks losing capital, businesses, jobs and tax revenue with them.
Britain does not become richer by having fewer rich people.
It becomes richer by enabling more people to create, earn, save and invest.
Stats Jamie | Stats, Facts & Opinions
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There is astonishing ignorance about this in the Labour party. I watched an interview with a woman labour MP and the discussion was about wealthy people leaving the country. "Good riddance to them" she says, "they don't pay any tax anyway". Well actually they do, quite a lot in fact.
How strange though. According to the Adam Smith Institute, my husband is a millionaire. Not because he has a million quid stashed away but because our house is worth over £700k and he has a good pension. It's not our fault the house is so expensive and I wonder who will be able to afford to buy it after us. Surely the ASI needs to be looking at multi-millionaires because of the distorting effect of the housing market.