The contrast could barely be starker. As last autumn’s conference season beckoned, and speculation about a snap election intensified, Labour’s prospects of securing a fourth term in power seemed good if not certain; David Cameron appeared likely to be the fourth consecutive Tory leader to have failed to make it to No 10.

How the political tables have turned. Twenty points adrift in the polls, it is now Labour’s chances of winning the next election which appear bleak. The economic downturn combined with the government’s failure to articulate a clear sense of direction and purpose have both played their parts. But so too has Labour’s failure to develop a clear and coherent case against Cameron. So what should that be?

Crewe and Nantwich showed that any attempt to run a class war campaign – focusing on the wealthy backgrounds of Cameron and many of his shadow cabinet – would be a disastrous mistake. It risks exposing Labour not simply to the charge of negative campaigning (and having nothing to say), but also to the notion that it is reverting to some of the old instincts which did it such electoral damage in the past.

What then of the suggestion that the author of the Tories’ rightwing 2005 manifesto is simply an unreconstructed Thatcherite, Michael Howard in converse trainers? As his poll lead has grown, the Tory leader has certainly appeared to slip back into the Conservative comfort zone. Cameron’s speech in Glasgow in July, with its attempts to bracket poverty with crime and addiction and its onslaught on the alleged ‘moral neutrality’ of the public sector, had echoes of Margaret Thatcher’s famed ‘Victorian values’. Surveying Cameron’s recent pronouncements, the Economist last month detected ‘a mini-revival of social conservatism’.

But to deny that the Conservative party has changed is to risk repeating the error of the Tories’ spectacularly ineffectual ‘New Labour, new danger’ attacks on Tony Blair. The more apposite charge is that Cameron’s politics are akin to an electoral weathervane, pointing in whatever direction he believes the popular wind to be blowing. In the face of rising oil prices, for instance, the Tory leader’s affinity for the green agenda has waned – a reflection no doubt of its diminishing utility to his rebranding of the Tory party.

It would be wrong, though, to just write Cameron off as ‘a shallow salesman’ without policies. As we demonstrate elsewhere (see pages 16-19), in health, education and welfare the Tories have set out detailed plans. As a coherent exposition of Cameronism, however, they are sadly lacking. In health, the Tories claim to want to put patients first, but appear rather keener to appease the vested interests of the BMA. In education, they say they plan to trust teachers more, but propose to impose an intrusive and regressive inspection regime. And in welfare, the Conservatives correctly argue that work is better than benefits, but appear to believe that charity and the voluntary sector alone can achieve this goal.

And here is the rub. As David Miliband suggested in July, the more substantive indictment against Cameron is that though he may desire the ends, he cannot bring himself to will the means. His dogmatic aversion to government activism both undermines his case against Labour and his attempt to fashion a modern conservatism. The hyperbole of his ‘broken society’ rhetoric is matched only be the paucity of the remedies he proposes: opaque references to ‘self-regulation’, undefined promises to support the family, and vague calls for the third sector to do more (despite, in many cases, it lacking the capacity to do so).

Labour needs to make clear, by contrast, that its attitude towards the state is a pragmatic one: government is a means to serve progressive ends – enabling individuals to lead more independent lives – but is not an end in itself. In order to make this case credibly, however, Labour still needs to shed the remnants of its statist past and go far further in redistributing power and control over our public services to both individual citizens and local communities.

And the party must also be careful not to allow Cameron to appropriate, as his Glasgow speech attempted to do, the language of personal responsibility. A willingness to talk about the importance of both rights and responsibilities was critical to ensuring Labour’s political recovery in the 1990s. The kind of clarity evident in James Purnell’s suggestion that the welfare state should offer ‘more support in return for more responsibility’ is, however, too often missing from the government’s message.

Forcing the Tories to return to the centre ground of British politics has been one of New Labour’s major political achievements. Having done so, Labour needs to contest that ground, not concede it. There’s a wrong way to do that and a right way. Over the past year, however, we’ve seen rather too much of the former than the latter.