The share of pre-tax income flowing to the top of the UK income distribution is significantly higher than it was in the early 1980s. This column explains the nature of top incomes in the UK and how they are taxed. Overall, the authors argue, UK income taxes are progressive, with average tax rates rising with income. But incomes from business ownership and investment are taxed at lower rates than employment income. With a reformed tax base, there would be a strong case to align tax rates across different sources of income.