Sitting on my desk at the start of this half term was an irate letter from the manager of the local Costa Coffee. He was frothing like a cappuccino about the behaviour of a group of our students in their week off. They were loud and broke a table, and he wanted the school to pay for the damage. I felt like knickers in a tumble dryer, a vertiginous giddiness of being in an unjust topsy-turvy world where I am asked to take responsibility for something over which I have no control.
This is exactly how I feel after this year's exams debacle, the impact of which is going to reverberate across the next five years. The English GCSE was bad enough, but that is only part of the story. We had odd results in all sorts of places: students predicted high grades in Year 10 modules got "ungraded"; appeals launched in A-level subjects resulted in regrades several levels higher and university places were missed as a consequence.
What other business could make such a catastrophic error and deal with it by issuing a new results form without a hint of apology or a whiff of regret for the distress that their incompetence has caused? I've received a more self-abasing letter of apology from Virgin because the train was 10 minutes late than any student ever gets from our avariciously arrogant exam businesses.
But this all pales into insignificance against the impact of two time bombs that are ticking away. First is the corrosive effect of all this on teachers' confidence. As exam marking becomes more and more erratic, teachers no longer have a clear sense of what they are trying to get students to do in order to succeed. They can no longer accurately predict grades to help plan career and university progression.
The second time bomb is the revelation of all that nonsense about criterion referencing. We naively assumed that if students met the criteria, they would get the grade. Then came the leak of the letter from Ofqual telling Edexcel to adjust the grade boundary because otherwise the percentage of grades above a C would be out of line with that cohort's key stage 2 results. It has been covert, under-the-blanket norm-referencing all along.
We have all bought into the imperative to raise standards. We tell kids to work hard and the elixir of everlasting grade-C success will be theirs. We thrash ourselves with more interventions than a human can reasonably bear to force the results up a few more precious percentage points. We believe that if we teach better and work harder, we will succeed in improving the education system and the results as well.
And all the time we were deluded. However hard we try, the results were not going to depend on our efforts, but were predetermined by what the cohort had achieved five years earlier in those magnificently dependable precision instruments, the key stage 2 tests.
This is not just moving the goalposts. It's playing lacrosse when you have been told you were playing water polo, with both hands tied behind your back and a double blindfold just to make life interesting. And all the time, Michael Gove sits on the touchline, saying: "I told you it was a mess, here's an English Baccalaureate Certificate to mop it up."
Roger Pope is principal of Kingsbury Community College in Devon.