If he is judged by the results of his policies, David Cameron will go down as one of the worst prime ministers in British history. His intentions were perfectly amiable, indeed progressive. To distance the Tories from “the nasty party” image inherited from Thatcherism, he proposed a “big society” based on empowerment of local communities and voluntary organisations. His policies, he said, must be judged by whether they would increase or decrease national “well-being”. But who now remembers his intentions? In practice, Cameron empowered his chancellor, George Osborne, to undermine the material conditions of personal well-being for millions; and he will be held accountable, in addition, for a broken political system.

Cameron must be given credit for understanding that GDP growth should not be the be-all and end-all of policy: that it was a means to an end, not the end itself. Moreover, the One Nation Toryism he espoused was far from ignoble. The idea of devolving more powers to local authorities, encouraging voluntarism, supporting charity work and opening government to public scrutiny was attractive.

In his heyday, commentators saw Cameron as heir to Benjamin Disraeli. But they might have already noticed the thin programmatic content of his rhetoric. Disraeli extended the franchise to the working class in 1867 and legalised strikes in 1875. Cameron legalised same-sex marriages, started a happiness index and passed an act further weakening the trade unions. The main reason for his vision’s emptiness was its marriage with hard-nosed Thatcherite finance. Cameron accepted, apparently without question, the idea that the great tent could be erected on the foundation of a penny-pinching Treasury. He failed to understand the extent to which state spending had become part of social provision – and political contentment.

The gap between Cameron’s big society ideal and public finance became a chasm when, as prime minister, he endorsed George Osborne’s austerity policy from 2010 to 2016. Osborne was the instrument, but Cameron must bear the responsibility. His own economic thinking was wafer- thin. It is encapsulated in his speech to the Conservative party conference of 2011. The road to economic recovery, he claimed, lay through debt repayment. Governments should emulate households in cutting down on debt and “living within their means”.

The fallacy is difficult to spot, which is why so many people still go on believing it. It lies in the failure to distinguish between households and governments, between what households need to do to stay solvent and what the government needs to do to keep the country solvent. On this fallacy austerity was built. The policy conclusion was dire. Government should not try to offset the decline in private spending by increasing its own spending; rather it should cut its own spending as well, hoping that the boost to confidence would cause private sector investment to boom.

This hope was unfulfilled, for reasons any Keynesian economist could have explained – and many did. If both the public and private sectors “de-leverage” at the same time, the direct result will be a fall in total spending and reduction in national income. For such effects to be offset by a revival of confidence would require a degree of myopia that is implausible even for our captains of industry. And so it turned out. Investment has not recovered to its pre-crash level. Economic growth has remained stubbornly “below target”. As a result, the government’s debt reduction goals have been missed consistently and borrowing has started to rise again as the new Chancellor, Sajid Javid, has scrapped the painfully erected fiscal rules. Public austerity, far from speeding up private recovery, slowed it down.

In fact, the economy has never really recovered from Osborne’s bloodletting. Headline unemployment, at 4 per cent, may be at its lowest level since the late 1980s, but it masks the big rise in under-employment – people working below their capacity and less than they want to, with a deterioration in the quality of jobs. And while asset prices have boomed and the wealthiest have gained relative to everyone else, the public services have been seriously underfunded. An estimated 8.3 million people are unable to keep up with debts, which are now above pre-crash levels. The young are set to be poorer than their parents, with many priced out of the housing market. The faltering economy seems set to judder to a halt, not just as the result of Brexit uncertainties.

As Cameron disappears into lucrative City employment, the abiding impression he leaves is of his superficiality. His fault was not one of physical but of mental idleness; of not thinking hard enough about how the different parts of his policy related to each other. Today’s crisis of governability is the direct consequence of his carelessness. People talk about the constitutional outrage caused by Boris Johnson. They forget that Cameron tore up a workable constitution to fix his short-term political problems. He conceded fixed-term parliaments to appease his Lib Dem coalition partners in 2010; and promised a referendum on the future of the EU to appease supporters of Nigel Farage.

The first weakened the power of the executive without establishing the electoral basis for coalition politics; the second destroyed the principle of representative democracy. He compounded his error by overconfidence that the referendum would produce a majority in favour of remaining in the EU, forgetting that after six years of austerity many voters were susceptible to a nationalist appeal.

All in all, the economic and political consequences of David Cameron have been pretty disastrous. He left a stuttering economy, an unworkable referendum result and a potentially paralysed government.