First-year economics students call it the Hog Cycle. Britons are more likely to call it a damned nuisance, as they find it increasingly difficult to bring home the bacon.
The long, hot summer - which put pigs off making bacon - and a rise in Japanese consumption have forced supermarkets to raise the price of pork and bacon up to 15 per cent, putting the artery- hardening the great British breakfast on the list of endangered species.
We eat a heroic quantity of bacon - 419,000 tonnes in 1995. But the shortage is not confined to Britain; it has been felt across Europe, threatening everything from choucroute to tagliatelle carbonara. Japan began to run low on pork last September, so it imported more from Denmark to make up the shortfall. Normally that would not matter; since the Danes, have more pigs than people.
But it compounded another problem in Britain. "We have a reduced breeding herd," said Sally Doyle, an analyst in the Meat and Livestock Commission. "There's been a big dip in the cycle so the number of slaughtered pigs available is actually declining and there is a great shortage on the market." In 1993, there were 800,000 pigs in Britain, but the latest figure shows that it is now down to 765,000.
Low prices over the last few years have not helped, Ms Doyle said. "Many pig producers went out of business, and so the herd went down." And the problem was exacerbated by the hot weather last summer, which put the pigs off sex."Conception falls when the weather is hot, so there weren't as many piglets coming through," Ms Doyle said.
The pig market has always been famously cyclical. Economists, noting the way that shifts in demand and supply failed to match, forcing prices up and down, coined the idea of the Hog Cycle. The main point is that making bacon, as it were, takes time, so supply and demand get out of kilter.
Economists found an answer to the Hog Cycle problem using something confusingly called the Cobweb Theorem, which tells you when the prices are likely to even themselves out. But that is unlikely to be of much help to Britain's greasy spoon cafes.
Price rises of more than a third have already been borne by producers. A spokeswoman for Tesco, where bacon prices have risen between 5 and 15 per cent, said: "Prices have risen across the industry . . . We've tried to hold our prices as low as possible." A spokesman for Sainsbury agreed.
Grenville Welsh, chief executive of the British Pig Association, warned that things would not improve unless the Government invested more heavily: "There is a lack of confidence in pigs at the moment," he said gloomily.Reuse content