Once upon a time, Bernard Levin ranted in The Times: "I long ago concluded that the present Government was worm-eaten, exhausted, dishonest, incompetent, lazy, mendacious …", ending 122 words later with "to say the least."

That was in 1994. Poor John Major. The hostility towards David Cameron is not yet of that order. Most commentators concluded nearly a year ago that the present Prime Minister was out-of-touch, arrogant, dishonest, incompetent, lazy, cowardly, indecisive, unprincipled and isolated in Europe.

I am not particularly a defender of Cameron, although I think he has been all right as Prime Minister. However, I do think that the criticisms commonly made of him are wrong. Some of them, indeed, contradict each other. First it is said that he and his ministers don't listen to advice; then that they make "humiliating" U-turns. An equally valid account of Michael Gove's decision last week to keep GCSE exams, for example, would be that the Education Secretary made a proposal, listened to views about it, including those of his coalition partners, and modified the proposal accordingly.

Other criticisms are contradicted by events. When Cameron promised a referendum on Britain's European Union membership, Labour and the remnants of the join-the-euro commentators said you do not get anywhere in European negotiations by threatening to walk away. Yet on Friday Cameron secured the deal he wanted on the EU budget, in alliance with his friend "Angela" and in opposition to his colleague "President Hollande".

Then there are the criticisms that cannot be contradicted exactly, but which can be undermined by imagining what the conventional wisdom might be if Cameron did as his critics suggest. Earlier last week, for example, it was suggested that he showed a deplorable lack of leadership in failing to come to the Commons to argue for gay marriage. We could see it in our mind's eye: he would do it well, swashbuckling and Blairite, as he persuaded the last five waverers needed to secure a majority of Tory MPs for equality.

But then we were reminded why that might not have been a good idea. The day after the vote, Cameron said at Prime Minister's Questions how "proud" he was to have brought the Bill forward. The MPs behind him listened in silence. If he had done a big Blair number the day before it could well have been counterproductive. And all the chin-stroking columnists would have said what a bad idea it was for Cameron to copy Tony Blair by defining himself against his party. As it was, a historic gain for equality was achieved without too much internal damage.

Finally, let us take the persistent notion that Cameron is lazy. Many of his Government's troubles, it is said, arise from his inattention.

I should confess that the unacceptable non-word "chillax" was first linked to Cameron by my colleagues James Hanning and Francis Elliott in the revised edition of their biography of him in May last year. They quoted a friend of his who wondered, admiringly, at his ability to put work aside and to chill out (or relax as we say in English) with family and friends. Hanning and Elliott thought that they were describing one of the healthier attributes of an unusually effective politician.

Again, we do not have to imagine what the conventional wisdom would be if Cameron spent less time playing Fruit Ninja on his iPad; we simply have to have a memory longer than a goldfish's, and to recall Anthony Seldon's assessment of Gordon Brown in his book, Brown At 10: "the most damaged personality to have become chancellor or prime minister since World War II".

So, my view is that Cameron consults about as widely as he should, and changes policy when the people he consults make helpful points. His policy on Europe is a Gaullist defence of the national interest that respects the right of the people to decide. His tactics on the gay marriage vote were right, and obtained the right result. And he works hard and effectively; he is good at absorbing a brief, at making decisions and at switching off to preserve his sanity.

The criticisms of him that matter, I think, are of his judgement. He didn't criticise Brown for borrowing at the peak of a boom. He opposed the nationalisation of the banks. In government, he allowed Andrew Lansley to lose his marbles at the Health Department and, when the NHS reforms started to go seriously wrong, he sent Oliver Letwin in to help him try to find them. He didn't see the danger to fairer constituency boundaries of messing up Lords reform until too late. And he misjudged the symbolic importance of cutting the 50p top rate of income tax. That error means that, no matter what the boring statistics say, which is that the richest 10 per cent are bearing and will bear the greatest burden of austerity, no one believes it.

Those are the criticisms of Cameron that should be made. If Levin were alive today, I hope it would be to Cameron's critics that he would address his tirade against the worm-eaten this and the lazy, incompetent that.

twitter.com/@JohnRentoul; j.rentoul@independent.co.uk