Mad cow disease was a terrible blow. Many flesh-eaters turned to fish and chips or vegetarian baltis, but it wasn’t the same. The meat industry insists that everything is all right now, but people are suspicious, given its track record of bluffing and blundering. Take, for example, the tale of scientists at the Institute for Animal Health in Edinburgh who spent five years looking for traces of BSE in 2,800 pureed sheep brains. At least that is what they thought they were doing.

The organs were collected in the early 1990s when the animals were thought to have died of scrapie, a disease similar to BSE though not harmful to people. But what if the vets had missed the real cause of death? After all, the sheep had eaten the same infected feed as the cattle that developed mad cow disease. What if they had really died of BSE?

Last August the Food Standards Agency announced that the Edinburgh results to date “could be compatible with BSE having been in sheep since the Nineties”. Scary stuff.

But then the experiment began to unravel. The scientists, faced with such a terrifying outcome, became nervous. The brains were old, decaying and, crucially, may have been contaminated with cow when they were collected. So they sent some to another lab for testing. They were given the all-clear.

But when they repeated the test last September the answer was rather different. One hundred per cent cow, said the laboratory of the government chemist. (The first lab, it later admitted, had - unbelievably - tested the wrong sample.) The reason for the blunder? Inquiries point to badly labelled bottles muddled up in the institute’s fridge. The result of the blunder? Five wasted years during which virtually no other tests have been done on the possible existence of “mad sheep disease”. Slam in the lamb, they say. Well, maybe.