Whole careers have worn out in the desperate battle to get the blasted females to cover up. Stratagems have been tried and failed: wheedling and force and blackmail and expulsion have been deployed to little avail.

Parents have been enlisted on both sides, and done precious little good to either. And still, year after year, in all but the most draconian schools, the girls strut and bare their flesh, undo buttons, thrust out cleavages, roll up waistbands and jut their defiant bellybutton-rings at weary members of staff who eventually grow too fed up and bored with the matter even to croak, “Oh, put it away, Chantelle!”

One day the history of this war will be written (probably with a few despairing footnotes about the corresponding war with the occasional ultra-devout Muslim girl who demands her human right to peer at the world through a narrow slit even during PE and science lessons). But when the final chronicle of heads-versus-female-flesh is written, there will certainly be a chapter devoted to the epatant Kesgrave affair which hit the press last week.

Kesgrave high school, a fine institution in my own home county of Suffolk, has become the first school to give up on trying to stop girls wearing indecent miniskirts, and insist that they all wear trousers instead. Since Kesgrave has a particularly fine record of having pupils walk and bike to school, it is a particularly pressing matter for them. Frankly, as someone who drives past their cycle lane once or twice a week, I can see why.

Sometimes, indeed, I can see everything. And so can the guy in the BMW in front of me, judging by the way he is weaving dazedly across the road as the Kesgrave Lolitas wiggle by.

Anyway, head and governors got so fed up with the pelmet-skirts and with the tedious and time-wasting task of nagging girls and parents about them, that they have called the little minxes’ bluff. They have decreed universal trousers. Shock, horror! There was wild talk of a legal challenge, of girls having their human rights infringed; but lawyers’ opinion so far is that the school is probably within its rights. After all, even the Equal Opportunities Commission has previously upheld the right of schools to stop girls wearing trousers, which I suppose implies that schools can drape children in any style of cloth they choose.

Nor do I hold out much legal hope for the doughty campaign being fought by that lad in Kent who goes to school in a skirt in order to prove some point I cannot quite put my finger on. I think he was beefing about the fact that girls could choose skirts or trousers at his school, but boys could only choose trousers. His parents, canny beings, merely say demurely that they are proud of the school for educating him to the point when he can think such philosophical issues through for himself.

Anyway, good for Kesgrave. It was time somebody introduced a new stratagem into the eternal conflict. Their cunning is admirable. The message is clear: if you girls can’t be trusted with skirts, you can damn well wear trousers.

Schools have to be cunning, because they have had a lot of weapons taken out of their hands in recent decades: not only the cane and the ruler and the “humiliating” punishment and the snap expulsion, but even the right to utter the sort of politically incorrect rebukes we used to get, along the lines of “Cover yourself up, girl, you look like a common tart”. Enforced trousers are a useful new ploy. Well done.

It won’t work, of course. In a war like this every new weapon provokes a new defence. Some girls will wear the trousers buttock-huggingly tight, so that nervous young teachers will never dare ask them to wipe the whiteboard in mixed company. Others will buy them two sizes too big and drape them from their hipbones just skimming the pubes, with sweaters stopping above the navel and puce thongs peeping out the back. Others will compensate for the cruel obscuring of their legs by unbuttoning still more of the front of their blouses or shrinking their school sweaters till they look like Jayne Mansfield.

The war goes on between girls heroically determined to look as porny as possible and teachers who would very much rather that they didn’t. Nobody will ever win.