David Cameron has been oversold. Just as he was being talked up excessively a year ago as the Tories’ saviour, the golden boy from Notting Hill, so now everything he touches seems to turn to dross. Both extreme views are wrong.

The rough patch that he has hit over the past few weeks is usual for an opposition leader. Ted Heath often had such periods in the late 1960s, as Margaret Thatcher did a decade later, and Neil Kinnock had them until his final two years as Labour leader. There are similar features: tactical errors, bad luck (being in Rwanda during the floods here), grumbling by disaffected MPs, stories of tensions among close advisers, and a critical press.

And, of course, a bad run of opinion polls - though the Brown bounce is only slightly larger than Mr Cameron’s own 18 months ago. Voting intentions can be volatile. But the latest Populus survey this week showed a big drop in leader attributes such as strength and having what it takes to be a good prime minister. But Mr Cameron remains ahead on charisma and likeability. Talk of getting rid of him is bonkers, a Tory suicide note that would be turned into a bigger Labour majority.

Mr Cameron has the correct basic strategy but winning power was always going to be a long job, just as it was for Labour in the 1980s and 1990s. It depends both on the governing party coming apart, and yourself becoming appealing.

The most important development recently has not been within the Tory party, but Gordon Brown’s impressive debut. Whatever doubts exist about his blizzard of initiatives, Mr Brown looks and behaves like a prime minister. He is establishing his own distinctive niche, although voters have not yet seen evidence that the change of government has made any difference to their own lives. The underestimation of Mr Brown, and his capacity to change, has been the Tories’ single most serious failure.

Summer offensives against Mr Brown are beside the point. Such attacks may be partially justified and will undoubtedly enthuse Tory activists, but they could rebound on the Conservatives. The only thing that matters for Mr Cameron is to define himself and his party. The current rows may help him to establish his own personality. The critics’ sole valid point is that voters and commentators alike have little idea about the shape of a Cameron government. “Social responsibility” or a “broken society” mean little in practice. The Tories want to reduce the relative size of the State. But how? The party is committed to taxpayer-funded schools, health and basic pensions, while complaining about squeezes on the defence and law-and-order budgets. Unless, and until, the Tories say how they would alter the size and role of the State, talk of cutting the tax burden (as opposed to cuts in individual taxes) rings hollow.

The policy reviews so far have been lively and interesting, and more are to come soon. But these are no substitute for a clear statement of what Cameron’s Britain would be like. This does not mean lots of policies. Without greater clarity, the grumbling about Mr Cameron will continue, and a bad short-term patch could turn into a long-term trend.

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