For a centre-right government, most of the traditional anti-inequality warhorses from the tax and benefits stable are of little interest. But not all of them.

“Inequality taken to extremes can overwhelm conservative ideals of self-reliance, limited government and national unity.”

This increases the chance of cross-party agreement that everyone, regardless of income, should be able to participate in society.

This looks like even more reason to do something about poverty in New Zealand.

Should the pay of an organisation’s highest earner be fixed at, say, 12 times that of the lowest paid earner?

This is a striking demonstration of how central inequality has become to our public debate.

Inequality matters for reasons that are far greater than economic growth. But the economy is paramount in the minds of many who still need to be convinced that growing income gaps are a problem.

Inequality is already very high, and has risen hugely since the 1980s, even before housing costs are taken into account.

Data assembled by Geoff Bertram shows New Zealand fitted the pattern of other countries set out in Thomas Piketty’s Capital in the Twenty-First Century.