The Sats marking fiasco this summer was bad enough for state schools in England. But behind the headlines, the longer-term issue was more fundamental than just another problem they have had to contend with.

The Sats crisis added a new twist to the spiral of advantage that independent schools have developed after two decades of political intervention in state education. Independent schools do not have to sit Sats and they enjoy freedom from state interference.

Trends in public opinion, backed up by the exam results themselves, indicate a damaging perception that independent schools have a built-in superiority over the state sector. It seems all the political pressure heaped on state schools threatens to backfire.

A recent poll on parental preferences, published by the Independent Schools Council, sounded ominous warnings. Some 57 per cent of those surveyed would like to send their children to fee-paying schools - up from 48 per cent in 2004. Even more worrying for Gordon Brown and Ed Balls, the Schools Secretary, 54 per cent of Labour voters would like to take this option - a figure that has shot up from 41 per cent four years ago. For a majority of a government’s supporters to think it has failed in such a key area as state education is disastrous.

The fine print of the survey carried disturbing messages for the Government. The independent sector was seen as providing high-quality academic education, the ability to develop children’s potential, and good university and employment prospects. These factors have allowed the sector to reach its highest level of potential since Labour took power in 1997. Clearly the Government’s state education initiatives have not won the battle for parental hearts and minds. Political intervention has proved counterproductive.

Politicians justify the relentless pace of change in terms of meeting global competition. But the consequence of their politicised initiatives may be to sap public faith in state education, leading to a tipping point where confidence can no longer be sustained.

Teachers have been accused of suffering from Stockholm Syndrome - where victims bond with their abusers as a survival strategy - willingly collaborating in damagingly ill-considered changes. This is unfair. In a world of permanent revolution, the priority is survival. When do teachers have the time to debate the trends that dictate their future?

Yet debate is imperative, particularly over the future of public exams. The Government has done itself no favours with its maladroit introduction of work-based diplomas and its abandonment of Blair’s two-track strategy preserving academic exams - GCSE and A-level. Likewise, Ed Balls’ decision to postpone the A-level inquiry promised for 2008 does not induce confidence, particularly with media reports of threats to academic education doing the rounds.

The Government’s position is that all exams will be reviewed in 2013. In the meantime, it plans to promote the diplomas as the “qualification of choice”. This has allowed the Conservatives to pose as the defenders of A- levels, a powerful strand in their current popularity.

Meanwhile, the consensus in favour of replacing academic qualifications with diplomas was weakened when the Confederation of British Industry came out against the new qualifications. There are no firm indications that diplomas will be successful, and their current level of support - 20,000 students in the first tranche - amounts to little more than a pilot study. As yet, there is no evidence they could replace academic exams in the long term.

It is against this background that A-level has come under the spotlight. Commentators have suggested that, since 2002, the well-publicised increase in A-grades, resulting in more than 25 per cent of candidates gaining at least one A, is largely driven by public schools and grammars.

This message was reinforced by the The Daily Telegraph in August. It analysed the 2008 results, arguing that the increase in A-grades from comprehensives was 3.9 per cent between 2002 and 2008, compared with a 9.1 per cent increase in the independent sector. The Department for Children, Schools and Families countered that, over the past five years, comprehensives “have been improving quicker than the independent sector”. The fact is only one of these positions can be correct.

For both political and educational reasons, a resolution has to be sought now, not in 2013. By postponing the A-level review, the Labour front bench may have bought time for their reforms to mature, but at a cost. The A- level debate has intensified, particularly focusing on grade inflation, hard and soft subjects, and the apparent ability of independent schools to increase their yield of top grades. These issues will not go away. If the independent sector is making gains more rapidly, we must find out why, and urgently.

Underlying the whole picture is a sense, confirmed by the Independent Schools Council survey, that parents are now coming to see the independent sector as offering stable, high-quality education for their children, against a state sector run ragged by politically motivated innovation. Education may be approaching a tipping point where the state sector cannot compete. A wise, statesmanlike schools secretary would bring forward the inquiry.

Trevor Fisher, Head of history in a Staffordshire tertiary college.