David Cameron's premiership must be considered a failure. He wanted to keep the UK in the EU, but failed; he wanted to preserve the Union but Scotland might well leave as a result of Brexit; and he wanted to heal a "broken Britain" but leaves the country divided and with hate crime rising.

A big reason for these failures lies in economic policy. Unnecessary austerity contributed to Brexit in four ways:

- In contributing to stagnant incomes for many, it increased hostility to immigrants, which some Brexiteers exploited. When combined with high inequality - which Cameron did little to combat - it also contributed to increasing distrust of "elites". It might well be for this reason that Theresa May has spoken of the need to abandon austerity and reduce inequality: she can now see - with the benefit of hindsight - that these have toxic political and cultural effects.

- In worsening public services, Cameron and Osborne allowed the false impression to grow that immigrants were responsible for pressure on the NHS. As Simon says, some people voted for Brexit because they wrongly thought that lower immigration would improve the NHS.

- Austerity policies ran contrary to the established wisdom of most economic experts. Having shut out experts in one area, Cameron and Osborne were then less able to appeal to them on the merits of staying in the EU. They created a precedent for a rejection of mainstream economics.

- Supporting austerity at home meant that the Tories could not argue for expansionary policies in the euro zone - policies which would have both helped to reduce migration to the UK and which would have diminished the image of the EU as a failing institution. This meant that Cameron could not argue that the UK was playing a positive role in Europe, and could not argue that staying in the EU would lead to a better EU. This meant that the wishful thinking bias was mostly on the Brexit side, rather than the Remain side.

Perhaps Janan Ganesh was right to say that the referendum was unavoidable - though that raises questions of why there was so little trust in representative democracy in the first place. What was all too avoidable, however, was the fiscal squeeze that probably tipped the balance in favour of Brexit.

In this sense, the costs of austerity have been far higher than estimated by conventional macroeconomic thinking. This perhaps reinforces an old piece of political wisdom - that if a government doesn't get economic policy right, it'll not get much else right either.