UK tax base depends on middle earners, not the rich — raising taxes on top 1% requires 4x larger increases elsewhere

A new analysis of UK income data from 2000 to 2023 shows the top 1% has captured a growing share of pre-tax income, while the middle-upper earners (50th–90th percentiles) lost ground. But the tax system still collects most of its revenue from the large number of ordinary earners, not from the wealthy minority at the very top.

This is a structural fact about the UK tax base that rewrites what redistribution actually costs. For years, policy discussion assumed raising revenue meant taxing the rich more heavily — the intuitive move when wealth concentrates at the top. This paper shows that even if the top 1% got significantly richer in the past two decades, they still represent a small numerator. The denominator is massive: tens of millions of earners in the middle and upper-middle of the distribution. That means any tax policy that relies on soaking the rich to fund anything — public services, transfers, climate spending — will run into a hard limit. You need to touch ordinary people's paychecks, or you don't raise the money. The numbers suggest you'd need tax increases on high earners to be four times larger than comparable increases on lower earners just to stay revenue-neutral. That's not a policy recommendation; that's the shape of the problem.