David Cameron was a prime minister who promised more than he delivered, and who ended in failure

David Cameron was an effective Prime Minister who promised more than he delivered and whose Government was cut short by an error of judgement that took Britain out of the European Union needlessly.

From the moment the voters delivered him an ambiguous mandate in 2010, he responded with alacrity and poise, forming a coalition with the Liberal Democrats to create a government that seemed to meet the needs of the moment. The people wanted a government that would restore order to the public finances while protecting the vulnerable and espousing liberal social values.

His central judgement on the economy, shared with George Osborne, his close ally, and with Nick Clegg, his coalition partner, was an overreaction to the financial crisis. The economy was already recovering and needed a continuing boost to demand. Instead, steep tax rises and deep public spending cuts administered a shock that stalled growth.

This stringency, dubbed “austerity” by its opponents, was quietly abandoned in 2012 – although the bedroom tax for those in social housing remained. The coalition ended up closing half the deficit by last year’s election, which was the target that Labour’s Chancellor Alistair Darling had set in the first place.

Mr Cameron’s economic record was flattered by the unexpected rate of jobs creation, which meant that unemployment fell to record lows. Most of the burden of deficit reduction was shared quite fairly, with incomes actually slightly more equal than before the financial crisis. But it did not feel like it for many people on low to middle incomes, and loose monetary policy helped push house prices ever higher, which meant that wealth inequality started to rise. These discontents contributed in the end to the defining disaster of Mr Cameron’s career: the European Union referendum.

Before that, however, we should recognise Mr Cameron’s achievements. He delivered equal marriage, a cause that drove defections from the Conservatives to Ukip almost as much as that of the EU. He kept a manifesto promise to devote 0.7 per cent of national income to foreign aid. The promising rhetoric of the “big society” brought forth the small but welcome National Citizen Service volunteering scheme for teenagers. And he led the country with assurance and the kind of communication skills needed when the pace of the media has speeded up so that almost everything happens at once, in real time.

On foreign policy, he tried to learn the lessons of the Iraq debacle, but the limited aerial intervention in Libya produced no better long-term results. He was embarrassed when the House of Commons refused to accept his plan for strikes against Bashar al-Assad’s regime in Syria to punish it for the use of chemical weapons, but no one emerges from the bloodshed in Syria with honour.

Two of his greater achievements were electoral ones. He won the Scottish referendum in 2014, which should have preserved the United Kingdom. But then winning the 2015 election against all the odds became the bittersweet hinge of his premiership. He tried to use the victory, and the ending of the coalition with the Liberal Democrats who were casually crushed, to occupy the centre ground with a finally detoxified One Nation Conservative Party.

But it didn’t quite work. He and Mr Osborne got the central Budget judgements wrong again: the “austerity” instinct came back to the fore, with a plan to cut tax credits for the working poor that was defeated in the House of Lords – but only postponed until Theresa May’s elevation now allows it to be rethought completely.

This mistake undermined the welcome rhetoric of Mr Cameron’s One Nation party conference speech last autumn, with its promise of an all-out assault on the causes of poverty, and an inspiringly idealistic ambition to reform the prison system. Even if this liberal, social-justice conservatism had not been too good to be true, it was really too late for it to be viable as lasting monument.

Then, suddenly, last month it became much too late. The Independent had criticised Mr Cameron for gambling unnecessarily on the promise of a EU referendum in his Bloomberg speech in January 2013. Ed Miliband was at his most statesmanlike as Leader of the Opposition in resisting pressure for the Labour Party to copy that promise, and in condemning the risk Mr Cameron was taking with the nation’s future for the sake of managing the Eurosceptics in his own party and of fending off the challenge for Tory votes from Ukip.

Mr Cameron’s judgement had often been erratic, but he had usually been saved by one of his graces – his readiness to make a quick and unapologetic U-turn, on everything from the sale of forests to the tax credits cuts. This time, however, he was trapped by that election victory. He failed to secure the meaningful restriction of free movement of EU workers he sought in his negotiations with European partners, and the referendum started to look as if it would be close.

Thus he ended up being the “heir to Blair”, as he had boasted before becoming Prime Minister, in negative as well as positive senses. Like Tony Blair, Mr Cameron was a centrist reformer and a good communicator. But like Mr Blair, he too made one crucial serious error of judgement that will tarnish his whole legacy.

He will be remembered by history as the Prime Minister who took Britain out of the EU by mistake. But perhaps we should recall him today for two of his more human moments. On 24 June, realising that his premiership was broken, he announced that he would be standing down as soon as a successor were elected. As he said, with his wife Samantha by his side, “I love this country and I feel honoured to have served it,” his voice cracked with emotion.

And then on Monday, as he announced that the new Prime Minister would take over this week, he sang to himself as he went back into No 10. Whether it was an attempt to steady his voice before the next business, or a moment of carefree demobilisation, it was a wonderfully British moment, and a fitting farewell.