According to the novelist W Somerset Maugham, every good story needs sex, class, religion and mystery. "'My God,' said the Duchess, 'I'm pregnant. Who did it?'" was his succinct model.
Last Sunday there were two teacher supply stories in the national papers.
The Observer suggested children across Britain were now being taught by "cut-price helpers" to save money. The Sunday Telegraph broke the story of Tristram Jones-Parry, head of chart-topping Westminster school who had been told by the General Teaching Council for England that he could not be registered to teach in a state school in spite of years of successful experience and a shortage of 3,500 maths teachers.
Both stories were based on questionable assumptions. But the one that caused a hue and cry that was to last for days after was not the thousands of children deprived of a qualified teacher but the slight offered to Mr Jones-Parry.
To his credit, the independent school head wished to "give a bit back".
Taken literally, there was nothing to stop him: volunteers in the classroom need no qualifications. Nor are there many obstacles left to prevent a state school paying him for his trouble, whether he has qualified status or not.
And it now seems there is indeed a way to recognise him as a teacher without sending him back to college or enrolling him on a training scheme.
So if nothing else, the furore has at least publicised this option to other suitable candidates.
As Mr Jones-Parry himself accepts, it is entirely reasonable that some formal check should be made on the qualifications and suitability of anyone who wants to teach in a publicly-provided school or work as a doctor in an NHS hospital. If there is a whiff of scandal here it is that so many parents apparently pay for private education where this is not a requirement.
There was no obvious sex or religion in this story and the only mystery is quite why it proved such a potent one. That leaves class.