Jonathan Reed: A day of blue skies for David Cameron, but Tory storm clouds are threatening

In a week that was supposed to celebrate the Tories returning to power, and prepare the ground for the comprehensive spending review in less than fortnight, the Prime Minister would have been frustrated that he was forced on to the back foot yesterday to defend the fairness of a policy that many of his colleagues say is unfair.

Three decades after Margaret Thatcher famously declared "The Lady's not for turning" in defence of her controversial economic policies, Mr Cameron was forced to make a commitment of his own as he made clear that he is not planning a climbdown, and that those on higher incomes – natural Tory supporters – will have to shoulder more of the financial burden. It was not the week that the Tory high command had envisaged.

Ever since the election, the nation has been force-fed a diet of doom about the state of the economy and the painful cuts to come. For all the talk of the Big Society, Ed Miliband, the new Labour leader, had a point when he used his inaugural conference speech to accuse the coalition of offering a "miserable, pessimistic" view.

The impact of all the grim talk, however, has been to soften the nation in preparation for the spending review on October 20. So extensive has been the list of projects and schemes deemed to be "at risk" that Ministers hope people will conclude that the impact of 25 per cent cuts in spending over the next four years will not be as bad as they had feared.

Take transport. By effectively putting every local transport scheme under review, Ministers will be able to come out after Chancellor George Osborne's announcement with a list of schemes still going ahead in spite of transport spending being squeezed. They hope the response will be almost as positive as the original decisions to back the schemes in question.

But this week's fiasco over cutting child benefit shows how much trouble is heading the Government's way – and how Ministers will have to be strong and resilient if they are to avoid being blown off course.

Just why the Tories decided to unveil the child benefit proposal this week is a mystery – conference should have been the chance to ease any anxieties about the concept of coalition government rather than picking unnecessary policy fights. It isn't the tearing up of the principles of universal benefits or even the fact that the better off are losing out – the elongated softening up exercise means most Tories, and many

in Middle England, accept the need for tough action to sort out the economy.

The problem is an anomaly which means a single income household earning 45,000 will be stripped of their money while the couple next door collecting 85,000 – both earning just below the higher rate threshold – are still quids in.

Cutting benefits from the better off may be fair, but discriminating against stay-at-home parents is not, particularly those mothers who believe that bringing up their children in a responsible and loving home is a full-time obligation.

And the handling of the issue left something to be desired, with the announcement made on breakfast television. Some Ministers claimed that they had only recently heard of the proposal – so much for the collective decision-making promised by Mr Cameron – and it was embarrassing that the PM had to apologise for excluding the policy from his party's election manifesto (even if it was refreshing to hear a politician say "sorry" for once).

The furore completely eclipsed what the Tory leadership hoped would be the story – a cap of 26,000 on the maximum amount any family can receive in benefits.

It will also rage on much longer than yesterday's speech – a speech that is unlikely to stick in the memories of much of the middle classes whose support the coalition is reliant upon.

Ministers still settling into life in government are quickly

going to realise that they will become deeply unpopular figures.

Some could learn a lot from Foreign Secretary William Hague, who made clear speaking to the Yorkshire Post that he is ready to roll up the sleeves and stay on course, saying: "When we announce things we will carry them through."

Yesterday, as Mr Cameron delighted the party grassroots with his praise of Margaret Thatcher and his guarantees on national security, he sought to convince voters outside the conference hall that the pain from spending cuts will be offset by the arrival of the Big Society, a concept the Tories struggled to sell during the election campaign.

It was his most extensive explanation of the vision so far, but the big question remains as to whether the public is ready to "step forward, not sit back" as the PM hopes.

The Tory attack on Labour spending may have been convincing and effective. But, when the cuts become clear, enthusiasm for the Big Society is unlikely to buy the Government much breathing space.

The skies may have been blue in Birmingham as Mr Cameron exited the stage, but the coalition needs to prepare for the storm that is about to hit Britain.