This is defined (I rely here on www.investorama.com, which looks and sounds authoritative) as “a long-term pattern of alternating periods of economic growth and decline. The cycle passes through four stages: expansion, peak, contraction and trough”. There is also, I find from The Social Science Encyclopedia, a Major trade cycle (no relation to the former PM), a Kuznets cycle and a nasty Kondratieff wave, under which we all nearly starve to death once every 60 years (sorry to spoil your new year, but the next trough of this one is overdue). But I can find no mention of the education cycle. Perhaps I can patent the idea and call it the Wilby cycle.

It is very closely allied to the business cycle, and goes roughly like this.

Every time there is an economic boom, teachers with transferable skills - notably maths, science and technology specialists - can take better-paid jobs outside education. Teaching recruits dry up because graduates see better career opportunities elsewhere. Married women reduce their hours as their husbands draw higher salaries and bonuses. Property prices soar and teachers cannot afford houses in central London or in the posher parts of the South-east. So we have a severe teacher shortage, with London and the South-east worst affected. The Secondary Heads Association warns of “meltdown”. The education department insists that there is no crisis at all. Children are taught by a succession of itinerant Antipodeans. Many schools move to a four-day or even a three-day week.

That is stage one and we saw it during the Barber boom of the early 1970s (Anthony Barber being the reckless chancellor in Ted Heath’s Tory government) and during the Lawson boom of the late 1980s (Lawson being Margaret Thatcher’s chancellor). Now, we see it again during what economic historians may call the Brown boom.

We then move to stage two. Ministers at last agree that something must be done.

Measures are put n train to make teaching more attractive. Salaries rise; special incentives are designed to encourage new recruits. This occurs roughly at the peak of the boom; indeed, given the propensity of politicians to leave extra spending to the last possible minute, teachers should expect a recession to start just after extra money arrives in their pay packets.

Now, stage three. Teaching suddenly looks a secure, affluent profession, with good career prospects. The economy begins to contract. Thousands are thrown out of work. Wage rises in the private sector dry up. Maths teachers can’t find jobs outside schools. Spouses of redundant executives return to teaching.

Graduates find that there are 1,000 applicants per vacancy at Price Waterhouse, so they “fall back” on teaching. Teachers can afford houses as prices have fallen, and their job security and the predictability of their future income flow makes them more credit-worthy than average.

Finally, stage four. Everybody hates teachers. They are in cushy, well-paid jobs, with short hours, long holidays and little threat of the sack. The recession is probably their fault, anyway, because the country’s workforce is too illiterate and innumerate to produce goods that anybody wants to buy. The Daily Mail demands a crackdown and shake-up. Schemes are put into place to “weed out” failing teachers.

Teachers’ pay rises barely cover cost-of-living increases.

Everything is thus ready for the next economic boom in which teachers are underpaid and undervalued while everybody else is in clover. Back, in other words, to stage one of the education cycle.

My cycle may not accord with all the historical facts but nor does any account of the business cycle. I am proud of my theory, as Major, Kuznets and Kondratieff were no doubt proud of theirs.

Politicians, on the other hand, who allow entirely predictable teacher shortages to occur again and again, have nothing to be proud of at all.

Peter Wilby is editor of the New Statesman