In the early 1980s doctors in Cambridge laid premature babies on lambswool, and the babies grew faster. They were the smallest patients in the hospital. 34 infants, born weighing about two and a half pounds, lying in incubators. The standard bedding was a cotton sheet. A psychologist and a paediatrician had heard that mothers in Australia and New Zealand put newborns to sleep on lambskins, and that the babies seemed more settled. So they ran a proper trial. Half the babies were nursed on cotton. Half were nursed on a pad of lambswool. Nothing else was changed. The result went into the Lancet in 1983. The babies on wool put on 22.7 grams a day. The babies on cotton put on 18.6. That is nearly a quarter more growth, in children for whom every gram is a step away from danger, from changing what they lay on. Nobody was entirely sure why. Wool holds a layer of still, warm air against the skin. It takes up moisture without feeling damp. It gives under a body where a sheet does not. Hospitals had known a version of this for a long time. For decades a patient who was bedbound was put on a sheepskin to stop the skin breaking down, and trials in Australia later confirmed that real sheepskin prevents bedsores. Then came the synthetic version. A sheet of polyester pile that could be boiled and cost a fraction as much. It looked the part. It does not do the job. A ewe grows the best thing ever found for a newborn to lie on, and a lamb is born onto it. The hospital tested that against the alternative and wool won. The alternative was cheaper, so that is what most babies get.

"Drinking milk is unnatural" is an argument made by people holding an oat latte, and it deserves a proper look. The objection is that milk was made to feed a baby cow. Correct. Now apply it to the rest of the trolley. A grain of wheat is the food supply packed for a baby wheat plant. You grind it up and call it toast. A nut is the same arrangement for a baby tree. A bean is the same for a baby bean. An egg was made for a baby chicken. Honey was made for baby bees. Almost everything you eat was put there for somebody else's offspring. Milk is simply the one that admits it. The second objection is that no other animal drinks the milk of another species. Cats do. Hedgehogs do. Dogs would, given a minute alone with the jug. Blue tits learned to open British milk bottles for the cream and taught each other the trick across the whole country. Seagulls in California have been filmed stealing milk directly from nursing elephant seals. No animal turns it down on principle. They only lack a bucket and a stool. No other animal ferments a soybean, sets it with gypsum and presses it into a block either. Nobody calls tofu a crime against nature. No other animal soaks oats in enzymes, adds rapeseed oil and a phosphate to stop it splitting, and sells it in a carton with a joke on the side. Milk comes out of a cow, who made it from grass, in a field. It is ready when it arrives. One of these drinks needed a factory, a chemist and a marketing department. The other one is being accused of being unnatural.

Britain was a mutton country until roughly 1955, and then it wasn't. Not lamb. Mutton. The red meat on the ordinary table, in the ordinary house, for six hundred years. The sheep stayed alive because a living sheep earned its keep: a fleece off it every June, lambs every spring, and it did the whole job on hillside that would grow nothing else. Only when all that was finished did it become dinner. The national dishes were built on it, and most people have no idea what was ever in them. Lancashire hotpot was mutton chops and kidneys under a lid of sliced potato, sat in the bottom oven from morning until the shift came off. Welsh cawl, mutton and leek and swede in one pot, the broth drunk first out of the same bowl. Scotch broth started with a piece of neck. Boiled leg with caper sauce was good enough for a Victorian dining room and cheap enough for a two-up two-down. Shepherd's pie is called shepherd's pie because a shepherd's meat was sheep. Look what it gets made with now. By the mid-fifties the trade had worked out that a sheep killed at five months turns money over twice as fast as a sheep killed at three years. That was the argument. Cash flow. The story about lamb's delicate flavour was assembled afterwards to explain a decision already taken in an office. What it costs you is not sentimental. Years on grass lay down proper fat, and mutton fat carries the compounds the rumen makes out of pasture, which is the actual flavour. The muscle is dark because it holds more myoglobin, and myoglobin is where the haem iron lives. A working animal puts collagen through its neck and shanks, and collagen under low slow heat turns to gelatine, which is why a mutton stew sets in the pot overnight and a lamb stew sits there like soup. Lamb is a four-month-old that has grown no fleece, raised nothing, and been bred lean into the bargain. Meanwhile a hill ewe who has given you five lamb crops and five fleeces is worth a fraction of her own offspring at market, because we talked ourselves out of eating her. Where it actually is, and it is out there: Your own butcher, first. If he says he has no mutton, ask for hogget, the one to two year old, and watch his face change, because it tells him you know what you are on about. He can nearly always get one in if somebody asks him twice. Native breed farms direct. Herdwick, Shetland, Manx Loaghtan, Swaledale. Most will put a box in the post and most are delighted anybody asked. Farmers markets and farm shops in any upland county, Cumbria, the Dales, mid Wales, the Borders. Ask the stallholder about cull ewes and see what he says. And Caribbean and West African grocers, where older sheep never went out of fashion and the customers know exactly what they are buying. Get a shoulder. Low oven, an onion, a pint of water, five hours, do nothing else to it. That smell coming out of the kitchen at four o'clock is the one your great-grandmother's whole street had on a Sunday.