predistribution. inequality

'Predistribution'

I assume that when people talk about 'predistribution' they mean the distribution of what ONS refer to as 'original income', which for people of working age is basically income from earnings and investment, before taxes, National Insurance contributions, government income transfers and benefits in kind. Targeting 'predistribution' as advocated by Labour leader Ed Miliband would therefore, presumably, involve trying to shift the distribution of original income.

So how has the distribution of original income developed over recent decades?