The Conservative Party has a stitch. It is a feeling familiar to anyone who was forced to do cross-country running at school. You set off at a gallop, arms swinging, and then, halfway round the football pitch, it strikes. You clutch your abdomen and lapse into a lopsided trot.

The Tories charged into government last year with a combination of Olympian confidence and adolescent impatience. After 13 years in opposition, they had a lot of pent-up energy, which they sought to unpent with a frenzy of reforms. Schools, prisons, the health service, the police, welfare - the zeal spread to every department.

Then came the stitch or, as it was officially designated in connection with NHS reforms, "the pause". The Health Secretary, Andrew Lansley, had to stop running altogether. Ken Clarke's liberal justice reforms are face-down in a muddy puddle of tabloid hostility. At the Cabinet Office, Francis Maude was meant to launch a white paper on public-sector reform in January. Much of it is written but the document has gone astray. It is now due, a spokesman says, "some time in the summer".

Watered down

Civil servants who, last year, were cheering the new government's vigour, now sneer at its disorderly retreats. "They just don't seem to have thought any of this stuff through," grumbles one Treasury mandarin. The feeling is mutual. A minister recently complained to me about the shoddy service provided by officials: "We are months behind because no one can even put an apostrophe in the right place."

But the problem is not civil servants with bad grammar; it is voters with long memories. The real cramp in the government's style is caused by an old sensitivity over the Tory brand.

David Cameron's four-year project to "decontaminate" his party's image in opposition was only a partial success. Residual fear of what the Conservatives might do to public services was a factor in Cameron's failure to secure a majority in 2010. Hooking up with the Liberal Democrats allowed him to pose as a non-tribal figure, governing across party lines, in the national interest. He was helped by Nick Clegg's initial strategy of owning the whole programme. The Lib Dem leader resisted the idea of carving up the coalition project into distinct yellow and blue portions, for fear that he would look like a bit player, begging for policy morsels at a Tory table.

The Lib Dems' catastrophic results in the local and Scottish elections in May and humiliation in the campaign for voting reform forced a change of plan. Now, the goal is to seek "definition" for the party within the coalition. That, Clegg's closest allies privately concede, amounts to a strategy of retoxifying the Tories. Then the Lib Dems might get some credit as a moderating influence.

Lansley's Health and Social Care Bill was the obvious first target. Opinion polls consistently show voters distrusting the Tories on the NHS. Long before the Lib Dems went public with their objections, George Osborne was growing impatient with the Health Secretary's bulldozing approach. It was the Chancellor who, in a crisis meeting this year with Clegg and Lansley, was banging the table, demanding the reforms be watered down.

One fear at No 10 is that the public hears the words "Conservative reform" and understands "mass privatisation". That anxiety helps to explain the disappearance of Maude's white paper. The proposals were supposed to open up vast areas of the public sector to competition from private companies and charities. In February, Cameron described this as a mission to "release the grip of state control". Only the judiciary and national security would be exempt.

By May, however, the tone had changed. Maude warned a private meeting of business leaders, eager to snaffle up the contracts for outsourced public-sector work, that they would be disappointed. According to a leaked memo, Maude told the Confederation of British Industry that "the government was not prepared to run the political risk of fully transferring services to the private sector, with the result that [it] could be accused of being naive or allowing excess profit-making by private-sector firms".

The right wing of the Tory party is appalled by this loss of nerve. It blames the Lib Dems and Andrew Cooper, co-founder of the Populus polling company, who was appointed as Cameron's director of strategy in February. It was Cooper's polling that first helped persuade Cameron that the Tory brand was contaminated. He has been heard talking about aspects of the public-sector reform programme as "second-term issues". Yet Cooper also offers comfort to the right. His recent surveys, showing the Tories looking "soft on crime", nudged Cameron into a U-turn on Clarke's justice reforms.

No such thing

The Prime Minister has done what he always does when worried about his image: he has relaunched the "big society". Last month, he announced new measures to support charitable giving and volunteering. This persistence baffles much of Westminster. By most measures, the big society is a PR flop. Voters are confused by it. Tory candidates struggle to sell it on the doorstep. Cuts to local authority budgets are starving the charities that are meant to deliver it.

Still, Cameron presses on. Partly, this is stubbornness. He believes he is on to something with the big society and won't stop talking about it until people agree. He also knows that chatter around the subject can help the party, even when the tone is dismissive. As one government adviser put it to me: "That the big idea people are talking about has the word 'society' in it is already a result in terms of the brand, when, not long ago, the only thing people knew about Conservative ideas was Thatcher saying there was no such thing."

The big society was hatched as part of the original plan to decontaminate the Tories and that project is unfinished. Cameron wants to be seen as the leader of a bold, reforming government, without sounding like a free-market fundamentalist, while the Lib Dems need voters to suspect the worst in all radical Tory ideas. Clegg has, so far, held back from trying to toxify the Prime Minister's pet project. We'll know the coalition has really hit the wall when the Deputy Prime Minister says, "There's no such thing as the big society."

Rafael Behr is chief political commentator of the New Statesman