I don’t know the answer here (yes, yes, thank you, I rarely know the answers to any questions) so perhaps someone can help? Seumas Milne:

The third is an increase in tax on the highest earners as part of a
wider programme of action to reverse the grotesque growth of inequality
that has scarred Blair’s Britain.

When we measure inequality we usually use some variation of Gini. 0.35/0.36 is, off the top of my head, around and about the number for the UK. Leave aside for a moment whether it’s important or not, whether we can alter it very much and whether we ought to try or not.

Do we measure this before or after the interactions of the tax and benefit systems? Both are, at least I think they are, modestly (at least) progressive. So after would provide a lower number than before.

But I have a feeling that we actually measure it before. Thus, changing the tax system will do nothing to change the number being measured.

Can anyone confirm this? Or refute it?