It is now a year since David Cameron and Nick Clegg stood in the Rose Garden of No 10 and promised a "new politics" in which "the national interest is more important than party". But the coalition government's record since those heady days is not one of which either man can be proud. The coalition agreement promised to stop the "top-down reorganisations of the NHS" but the government's chaotic reforms have destroyed trust among GPs and nurses. Youth unemployment has continued to rise and currently stands at 963,000 (20.4 per cent), the highest level since records began. Most universities now plan to charge fees of £9,000 a year, despite ministers pledging that they would do so only in "exceptional circumstances". And, worst of all, an economy that was growing at an annual rate of over 4 per cent when the coalition entered office has been stagnant for the past six months.

Despite all this, it is Mr Cameron who is in the strongest position of the three main party leaders. His robust intervention in the Alternative Vote referendum is credited with securing a victory for the No campaign and the Conservatives won more seats in the 5 May local elections than they did in 2007. Tory voters are getting the kinds of policies they expect from a Conservative-led government, not least the plan rapidly to reduce Britain's £141.1bn Budget deficit.

Yet in the first year of the coalition Mr Cameron's leadership flaws have become all too apparent. He is convinced of the need to cut both the demand for and the supply of the state, but his lack of attention to detail is largely to blame for the government's botched reforms to the NHS and higher education. As Tim Montgom­erie, editor of ConservativeHome, notes on page 32: "Cameron's ministers describe his dismissive wave of the hand whenever a conversation becomes focused on the detail of an initiative."

But the Prime Minister's troubles are as nothing compared with those of Mr Clegg. By choosing to present the coalition as an ideological union, rather than a temporary alliance, the Liberal Democrat leader needlessly alienated many of his party's natural supporters. If he is to regain some of the credibility he has lost, Mr Clegg must call a halt to the coalition's most destructive reforms, starting with Andrew Lansley's marketisation of the NHS.

The scale of the challenge simultaneously facing Labour is clear. The defeat of AV, combined with the Scottish National Party's victory in Holyrood, means that it has been deprived of two opportunities to undermine the Tories. Two weeks ago, we warned that failure in Scotland would be a big blow to Ed Miliband's leadership, and so it has proved. The spectre of Scottish independence is one that rightly terrifies Labour. Few doubt Mr Cameron's commitment to defending the Union, but, for many in his party, which has just one Scottish MP, the prospect of an independent Scotland is attractive.The break-up of the United Kingdom, combined with planned boundary changes, could herald an era of Tory hegemony at Westminster.

Labour's disastrous performance in Scotland and its mixed showing in England demonstrate the need for Mr Miliband to offer a clear route back to power. Unlike Mr Cameron, who became leader of his party at a time of economic and political stability, the present leader of the opposition cannot afford to wait for the outcome of a two-year policy review before presenting a coherent alternative to the government's plans. As the local election results demonstrated, it is not possible for Mr Miliband to construct a majority on the basis of disaffected Liberal Democrat support alone. If Labour is to be viewed as a potential government, it must show that it can take seats from the Tories in England as well.

It is regrettable that none of the three leaders has offered a vision of an economy that combines redistribution with growth. In the months ahead, progressives of all parties must develop a plan for the political, cultural and economic renewal that Britain desperately needs. The voters, who are facing the biggest fall in living standards since the 1920s, deserve nothing less.