In Evelyn Waugh’s Decline and Fall, Paul Pennyfeather visits Church and Gargoyle, scholastic agents, in search of employment and is told that they divide schools into four categories: Leading School, First-rate School, Good School, and School. Turning this on its head, those who now run education - ministers, senior civil servants, inspectors - seem to divide teachers into Utterly Incompetent Teacher, Third-Rate Teacher, Not Awfully Good Teacher, and Teacher. The management in Whitehall may have changed but the rhetoric has not.

So what is it about teachers that invites so much knocking copy? Why do even the people who largely depend on teachers’ support or custom - Labour politicians, editors of The Guardian, for example - sound as if they despise the profession? Why, when I try to defend teachers, even when talking to people whom I would normally regard as political allies, am I treated as though I have been duped by Doug McAvoy or Nigel de Gruchy and gone soft in both head and heart? Why is there so much talk of incompetent teachers, but not of incompetent doctors, nurses, police or civil servants? And why is this teacher-bashing (a sport that the Labour party would deplore if it were directed against any other minority) apparently confined to England? Even in Scotland, teachers seem to retain some of the social standing and respect that they enjoyed 40 years ago.

I suspect that, historically, teachers are victims of the English class system, trapped between envy from below and snobbery from above. From the working-class point of view, teachers had it cushy: long holidays, short hours, good pensions, stable employment, next to no threat of the sack. Teachers may have thought it hell to be trapped in a classroom with 30 or 40 children but it was worse hell to work all day underground or in a noisy factory. That so many teachers themselves came from working-class backgrounds only made envy sharper.

To the middle-classes, on the other hand, teachers were objects almost of derision: shabby, unworldly, plodding, slightly comic. They were the people who hadn’t quite made it, the sixth-formers whose A-levels weren’t good enough to get them into university. Teaching was something for those down on their luck. “I expect you’ll be becoming a schoolmaster, sir,” said the college porter to Paul Pennyfeather. “That’s what most of the gentlemen does, sir, that gets sent down for indecent behaviour.”

I detect the echoes of these ancient prejudices in much of the present political debate: the twin assumptions that teachers are second-rate people and that they have an easy time of it. I detect two other echoes. First, the long-standing English suspicion of education and intellect, which derives from a nation that became a great power through a combination of brute conquest and inventive wit. Britannia, after all, ruled the waves when around half the population was illiterate. I am not suggesting that anyone, left or right, now favours illiteracy but I do find, in all the talk about “accountability”, the hint that schools, if not watched carefully, are just a waste of everybody’s time and money.

Second, I hear an echo of the crisis of English identity. Education traditionally tries to give children a sense of the values, the culture, the goals of the society in which they live, and not necessarily in the proselytising sense. But the English have lost all idea of who they are. Think of how Tory leaders veered, in the most bizarre fashion, between nostalgia for a vanished world of village greens and warm beer, on the one hand, and aspiration to become a European version of Hong Kong on the other. Most teachers would be uncomfortable, and rightly so, with the values and goals implied in either vision. But the lack of an agreed alternative leaves them without a role, save that of getting children through exams. All the English know about themselves is that they want to make more money, an ambition of which they are faintly ashamed. Though Tony Blair thinks that the secret is “education, education, education”, it doesn’t seem to leave teachers with a very dignified or heroic place in the scheme of thing. The best they can hope for, I suppose, is to be celebrated one day for exceeding their targets, rather like collective farmers in the old Soviet Union.

But, above and beyond all that, there are more proximate reasons for teacher-bashing. First, the ideals of disinterested public service that used to motivate teachers are simply not understood in the post-Thatcher world. Our language, our culture, our institutions have been transformed so that we recognise money and personal advancement as the only motivators. We no longer accept that people may work for esteem or respect or personal pride or for the simple satisfaction of, for example, seeing a former pupil get a first-class honours degree.

Thatcherism wrought such changes that new Labour could not be expected to reverse them in a few weeks. But does it, as far as teachers are concerned, want to do so? I fear not. If anything, new Labour will give teachers a harder time than the Tories did, for two reasons. First, the Blair leadership looks to the London chattering classes for its moral sustenance and its social networking, to say nothing of its election funding. These people - lawyers, architects, journalists, academics, theatre, film and television folk - like to think they are liberal and egalitarian and had hoped to send their children to state schools. But the condition of state schools horrifies them and, at inconvenience to their consciences, they have to pay school fees or, like the Blairs, transport their offspring across the capital to what are, in effect, selective schools. Somehow, they had hoped, city comprehensives would be like the grammar schools or whites-only suburban primaries of their youth - quiet, orderly, academically-focused. Teachers failed, unsurprisingly, to pull off this miracle, and they will not easily be forgiven.

Second, governments through the ages have needed scapegoats, enemies within or without: Jews, communists, blacks, Swiss bankers, trade unions have all served their time. The last government hit on Brussels and perfidious continentals. If its successor really does believe that education is the secret of national success, it makes perfect sense to choose teachers as the new enemy, particularly when things start to go wrong. The next five years could be depressing indeed for TES readers.