Teaching’s been turned on its head. The profession that was once a by-word for doing nothing (“those who can’t, teach”) now mixes it with the best of them. Teachers don’t simply teach any more, they sell. There was a time they encountered the word “salesman” only in Arthur Miller plays; now they’re adopting many of the tactics of another famous Arthur - Daley.

You doubt it? Study your local paper. See how many school open days are on every Saturday. Nothing to do? Fancy some free coffee and biscuits? Want to be cosseted by some of the best brains in education?

Simple. Come along to one of these open days. You’d pay a fiver for the privilege of going round some National Trust house, so why not take a free peek around the portals of one of England’s public schools? You’ll be pandered to by senior staff, ushered round by charming sixth-formers, and generally given the red carpet - all on the 1,000-to-one chance you might send your child there.

Or come along to an Independent Schools Information Service exhibition. They’re springing up like mushrooms all over middle England. ISIS (what an impressively Oxonian acronym) will book a civic centre, theatre or sports hall in some provincial town and charge all the local independent schools a hefty fee to take a stand.

What’s behind all this sudden activity? The chill winds of harsh economic reality, swirling around the cloisters of Britain’s schools. Teaching has become as competitive as the used car trade. The days of pipe-smoking headmasters smugly sitting in studies, waiting for punters (“for what?”) to form an orderly queue to put little Johnny’s name down for Thwackford Lodge went out with the Austin Cambridge.

So these open days and exhibitions are full of teachers trying to sell something: their schools. Hence the entertainment value: historians acting like hustlers is not the most dignified spectacle.

In true Daley style, someone must be making a nice pile out of all this. The hi-tech foldaway display stands do not come cheap. Yet overnight, like some safe and sanitised Glastonbury, whole walkways of them spring up - festooned with bunting, stickers, balloons, pens, monitors (no, not that sort, TV monitors for the pound;50,000 promotional video) and, of course, plenty of glossy prospectuses. Nice little earner, Terry? It’s a right result (and we’re not talking A-levels).

What’s most entertaining is that a large proportion of the punters have no intention of purchasing the product on display. After all, who’s going to shell out the price of an Aston Martin on a sudden whim in a hall - especially when the “salesman” is a bored teacher doing a crossword?

These days are best viewed as events at which, unlike the car showroom, the punter is in control. No HP forms, no pressure. He or she can have as much fun as he or she wishes, stringing the school along, picking up expensive pens, promises and prospectuses and exchanging friendly badinage, flirting even, with Oxbridge-educated heads.

And there’s no obligation. How’s that for a good deal? No cash changes hands; nothing’s even sold. Chances are - just like the Miller play - you won’t even meet a decent salesman. How’s that for the economics of Arthur Daley turned upside-down?

Andrew Cunningham is an English teacher in Cranleigh, Surrey