Gordon Brown is arguably the most economically literate head of state in the world. Which is maybe why he felt comfortable tinkering with the UK’s income-tax system. But as John Kay says,
Tax is always more complicated than you think and the results come back to haunt you.
Brown’s political future could be in jeopardy here, and a large part of the reason is that people have difficulty understanding the difference between average and marginal tax rates. It’s a pitfall which faces many sophisticated politicians: they think they can communicate ideas which are clear to them but which are not clear to the general public. And most of the time they’re wrong.