Exam results are, of course, "fixed" every year. Examiners double-check papers that the mark scheme places near the boundaries between grades. If necessary, those boundaries are then adjusted to ensure similar standards apply from year to year.
What seems to have happened this year is that the new and more modular approach to AS and A2 levels meant many students had already achieved high grades on earlier exams. So the boards raised the grade boundaries dramatically on some of the remaining assessments to keep down the numbers of overall A and B grades.
The result: hundreds of teachers and thousands of hardworking students disillusioned by a system in which they placed their trust. Many believe their lives have been blighted by a crude political fix.
No doubt ministers did not understand what was going on, let alone order it. But the boards had already been publicly pilloried by Estelle Morris for a series of high-profile blunders and widely accused by others of grade inflation. So they well understood the political fallout of any jump in top grades.
In fact ministers should have known what was happening. Their own Qualifications and Curriculum Authority, which monitors grade-setting exercises, should have told them and advised on the best way to maintain public confidence in the changes being made to such a high-stakes exam.
Now we await results of an inquiry carried out by a body that is itself deeply implicated in this debacle. The QCA, without effective leadership since last year and apparently unable or unwilling to raise awkward questions, has failed in its watchdog role. What confidence then can we have in its report? There must be an independent inquiry and the QCA's brand new chief, Ken Boston, should welcome it.