John Howard, Peter Costello, Joe Hockey ... Every living Liberal treasurer but the latest has wanted to tighten the tax treatment of trusts.

Howard did. As more and more high earners used discretionary trusts to divert income to children, some very young with tax rates of zero, he amended the law in 1980 to tax payments to them at the top marginal rate, just as if they had been made to the people actually making the investments.

Opposition Leader Bill Shorten has said tackling inequality will be Labor's defining mission going into the next election. Credit:Daniel Munoz

As prime minister he commissioned business figure John Ralph to conduct an inquiry that recommended he close the same loophole for adults by taxing payments to them at the company tax rate, even if (especially if) those adults were stay-at-home spouses on tax rates of zero. His treasurer Peter Costello took up the idea and then shelved it under pressure from other members of Parliament.

As shadow treasurer before taking the job Joe Hockey said trusts should be taxed as companies, regardless of the tax rate of the apparent recipient.