The Prime Minister is well qualified for the job in at least one important sense: he is lucky. He is lucky that Nick Clegg has absorbed most of the opprobrium directed at the coalition in its first year. From some of the press coverage recently, a Rip Van Winkle might rub his eyes and conclude that Mr Clegg was the most evil man in Britain. Yet anyone who has actually been awake during the past 12 months must know that Mr Clegg is trying to promote the values of social justice and toleration for which his party stands. As John Rentoul argues today, one may disagree with the way he has gone about it, but one should not doubt his sincerity or seriousness of purpose.

David Cameron has been lucky, too, to face a weak leader of the opposition. Ed Miliband has barely registered with the British electorate. While the Labour Party was right last year and remains right now to argue that public spending should be cut on a shallower trajectory than the Conservative plans, it failed miserably to turn last week's local elections into a referendum on George Osborne's spending cuts. Labour made 800 gains, but they were at the expense of the Liberal Democrats and independents, while the Conservatives actually increased their representation on local councils.

Mr Cameron was lucky that Labour was hopelessly divided over electoral reform, and that Mr Miliband was unable to show leadership on the issue. Mr Cameron was lucky that the fate of the referendum turned partly on how much of the centre-left electorate felt about Mr Clegg. The Prime Minister was also ruthless enough, when the outcome of the referendum seemed in doubt, to mobilise anti-Clegg sentiment when it suited him. And he was lucky, both in the referendum and in everything else, to have most of the press behind him.

He has, of course, been lucky from birth – and he has always been lucky in his ability to cram for an exam at the last moment. At Eton he was an indifferent student until his A-levels; at Oxford he rose to the challenge of a First. As a new MP, he was lucky that David Davis, such a certainty as "next Tory leader" that he had signed up nearly every careerist in the parliamentary party, ran such a poor campaign.

As Paul Goodman, the former MP, pointed out on the Conservative Home website on Friday, he was lucky to become Tory leader when he did, "towards the end of a governing cycle for Labour". He was lucky, "in all likelihood, that Gordon Brown didn't call an election in the autumn of 2007".

Mr Cameron has been lucky even when he seems unlucky. He failed to win a majority in last year's election – we would argue that this was because his deficit-cutting plan was too harsh – and yet the Tories won enough seats to ensure that they were the only partner with whom the Liberal Democrats could form a coalition.

Even the unexpected triumph of the Scottish National Party last week could well play into the Prime Minister's hands. With a mere 14 per cent of the vote in Scotland, the Tory leader can rally his troops, especially in England, with a rousing call to save the Union ("every fibre of my being" and other clichés), while challenging Alex Salmond to hold a referendum on the principle of independence. That is a referendum that Mr Salmond professes he wants but which he knows he would lose.

The Independent on Sunday wonders how long it will be before Mr Cameron's luck runs out. With the alternative vote referendum out of the way, it is time for politics to move to a new phase, one in which the Conservative Party is held to account for its responsibility for the big issues of tax and spending. Chris Huhne, the Climate Change Secretary, writes today: "No government anywhere in the world has been able to tackle our scale of fiscal problems and become more popular in doing so." Unfairly, that is not yet the case. In this government, the junior partner has become more unpopular, while the Conservative Party still rides high. In part, this may be because the cuts have hardly started yet. That is now going to change. Mr Osborne needs to drop his disappearing act, copied from Gordon "Macavity" Brown, and defend his own policies.

This newspaper at least recognises that Mr Clegg is not the main obstacle to greater fairness in this country. Mr Cameron and Mr Osborne must not be allowed to get away with their cuts scot free.