Louie Brockbank is a researcher at the Legatum Institute.

The shock Conservative victory in May is already indelibly recorded in the annals of British political history, as ‘the one the pundits got wrong’, with David Cameron’s party defying the predictions of every opinion poll to win a majority for the first time in 23 years.

Red-faced pollsters swiftly announced their intention to hold a formal inquiry into how their sophisticated surveys proved so inaccurate, and a consensus has emerged that many voters simply hid their intentions until the last minute, with the ‘shy Tories’ of 1992 returning to break Labour hearts once again.

Amid all the explanations emphasising (undoubtedly significant) reasons like the ‘SNP factor’ and the deficient leadership of Ed Miliband, it is easy to lose sight of the extent to which the electorate’s decision rested on the economic fundamentals, and in particular whether Conservative economic management was judged unfavourably enough to make a switch to Labour the rational choice.

The Legatum Institute’s global Prosperity Index, published today, helpfully refocuses the ongoing debate on the result around the big economic arguments between the parties, and offers some concrete reasons for the majority no-one predicted. The UK findings, based as they are on 2014 data, suggest that Conservative success rested on a pronounced shift to more optimistic economic expectations among the population at large during the course of that year. This uptick in confidence about the economy was sufficient to allow Tory claims of Britain being on the right track to ring true for enough voters for them to maintain and then enhance their electoral position. This in turn allowed Cameron to take his place in history as the first Prime Minister to have increased his party’s vote share after a term in office since Lord Salisbury in 1900.

The Index suggests that the Conservatives were saved by general economic expectations catching up with economic reality in the months before the election. The great British jobs boom got underway in 2013, when unemployment began heading steadily downwards, but pessimism continued to stalk the labour market, with last year’s Index recording that just 18 per cent of Britons felt it was a good time to find a job. The 2014 statistics in this year’s Index show that indicator rose to 49 per cent, meaning the Prime Minister’s pleas that ‘the plan is working’ dovetailed with what a large section of the population themselves felt to be true. This dramatic shift towards a rosier view of job prospects should be seen as significant in – particularly in light of a Conservative campaign focused on the needs of middling and low income employees, for instance through its emphasis on the raising of the income tax threshold and promises to raise it even further.

Popular attitudes to individual opportunity and the link between effort and success can also be seen as having shifted the Conservatives way, with the proportion of Britons believing people can get on in life through hard work rising from 84 per cent to 88 per cent between 2013 and 2014, the culmination of a significant medium term rise from the 78 per cent recorded in 2007. Again, the Tory pitch of governing for those ‘who want to work hard and get on’ can be seen as resonating with a large and growing section of the population, allowing the party to enter election year as the beneficiary of an ongoing attitudinal shift that favoured its rhetoric and policy offering.

Conservative success can also be ascribed to a substantial shift in perceptions of how easy it is for entrepreneurs and new businesses to succeed. The index reveals a sharp improvement, with the proportion thinking Britain a good place to start a business rocketing from 48 per cent in 2012 to 70 per cent in 2014. Crucially, this should be seen as laying the foundations of electoral success not just in what it implies about the governing party’s skill at economic management as it is perceived by the average voter, highly significant though that is, but because the self-employed and small business owners constitute a growing section of the population (and therefore the electorate). A full 15 per cent of the workforce, up from 13 per cent in 2008, now fall into this category; the Government’s attitude to entrepreneurship and enterprise directly impacts on their ability to make a living, and their votes are likely to be given to the party which can prove its commitment to maintaining an entrepreneurial environment. The substantial rise in optimism for start-ups must therefore be understood as impelling a substantial and growing bloc of voters towards the Conservatives as well as making the average voter more likely to feel they were making a good fist of running the economy overall.

This rise in start-up optimism, alongside that for employment and the likelihood of succeeding through hard work should be seen as shifting the pitch very much in the Conservatives’ favour before the election year even began. The Prime Minister’s appeal to Britain in his 2014 conference speech to allow his party to ‘finish what we have begun‘ therefore appeared credible to a growing group of voters, reflecting as it did their own assessment of the outlook for their own employment and businesses. The shift in opinion that swept Cameron and his Party back into Downing Street was therefore afoot long before the prospect of a goofy Prime Minister Miliband in hock to Sturgeon’s separatists began to curdle the blood of Middle England. A critical mass of the electorate accepted the efficacy of Tory economic policy during 2014. The party’s necessary role during this year’s election was more that of presentation and a relentless focus on the link between economic success and continued Conservative incumbency.

However, the Prosperity Index findings provide no unalloyed joy for those of a Tory disposition, and in fact serve to confirm the reality that the party is far from loved, and its motives distrusted. The economic fundamentals, at least in terms of popular perception recorded by the Index, favoured the Tories by the end of 2014, but this greater optimism about the economy was at no point translated into a clear poll lead for the party with a fair claim to have been its architects, with the Conservatives’ reward only arriving with the 10pm exit poll on election day. A majority-granting bloc of voters were persuaded by Conservative policy during 2014 but refused to declare this other than in the privacy of the ballot box.

Cameron has said he intends his political legacy to be a ‘One Nation’ Conservative Party, dedicated to building ‘a Greater Britain’ for all her citizens. It remains to be seen whether the 2020 Prosperity Index will bear out this grand plan.