There will be no classes in more than 1,000 schools today because of a teachers' strike called by one in ten teachers, against the advice of five out of six teachers' unions, in violation of a pay deal approved in advance by all six of those unions. The sixth - the National Union of Teachers (NUT) - has called the strike over salaries and the profession's failure to recruit and retain enough new members. It has a worthwhile point to make on pay, and a vital one on teacher attrition. But it could hardly have chosen a more counter-productive way to state its case.

The last national teachers' strike was in 1987. Since then the Conservatives, under Mrs Thatcher and her successor, failed conspicuously to deliver the investment or reform that the state sector urgently needed. From 1997, the Labour Government has at least delivered the investment. Total spending on education has more than doubled since then. Much of the new money has been earmarked for infrastructure, but average teachers' salaries have risen over the decade by 15 per cent in real terms, and those of head teachers by nearly a third.

The NUT is right that its members have received below-inflation pay rises for the past three years. It is also reasonable to measure pay against the Retail Price Index that reflects most householders' experience of inflation (now running at 3.8 per cent), rather than the Government's preferred Consumer Price Index (currently 2.5 per cent). But over the past decade as a whole, teachers have fared well on Labour's largesse - and the labour market has responded: teaching is now the second-most popular career choice for graduates. The Government has also nurtured goodwill in the profession by involving teachers' unions in the details of policy-making as never before. The net effect, for teachers as opposed to pupils, has been an unquestionable boost to their prestige - prestige that the NUT has today chosen to squander.

The union will almost certainly emerge from today's strike more bruised than the Government. By ignoring the conclusions of the independent pay review body whose findings it had previously promised to accept, it is inviting Whitehall to stop taking it seriously. By calling the strike so close to the exam season and in the middle of the week when most schools reopen after the Easter holiday, it is causing maximum disruption to parents and children, who are not parties to its dispute. And by defying the preference of every other teachers' union it is advertising the extent to which its leadership is still guided by outdated ideology.

The axiom that parents trust teachers more than politicians may not, therefore, hold today. But this does not leave the Government in the clear on broader questions of educational reform. Far from it. Parents who back it against the NUT have every right to demand why their taxes have not been put to better use helping the least able in secondary schools, 23,000 of whom left school last year without a single GSCE; or the most able, who face a shameful shortage of specialist science and modern language teachers which the Government has the gall to blame on pupils' own lack of interest in the subjects. Ministers can afford to ignore the NUT's unrealistic demands on pay. They cannot afford to ignore parents' demands for better schools.