The number of millionaires living in Britain has hit the lowest level since the financial crisis, new research suggests. The figure of 442,000 is the lowest level since the 2008 financial crisis . The think tank also warns that calls for a wealth tax are misguided. Palmer added: “Recently mooted anti-wealth proposals, such as a wealth tax or equalising the capital gains tax rate with income tax, will only make this problem worse. Many wealthy people may be concerned about calls for a wealth tax or higher taxes.