More income tax on high earners won't fix things. It's time to limit the Isa allowance

Like most people in their 50s with PhDs in economics, I am in the top 10% of the income distribution.

- Tim Leunig

But it wasn't always so - my mum was a cleaner, and we were clearly in the bottom 10% when I was a kid.

The point of the Labour party is to help families like the one I grew up in. Labour needs to reduce child poverty if its existence is to have any purpose. Growth alone will not be enough, so this moral mission must be funded, in part, by taxing richer people. Rachel Reeves says this will be "part of the story" of her budget at the end of November. But how, exactly, should the government tax people like Tim?

Raising income tax rates on reasonably high earners does not work very well. When tax rates are too high, people who don't need the money stop working. They can decline overtime, move to a four-day week, or simply retire early. The Institute for Fiscal Studies (IFS) found that raising the higher rate of income tax in Scotland raised little or no revenue. Higher income tax rates on the most affluent would not raise a lot of money in the UK, and might reduce national income.