Porridge, more than most foodstuffs, divides people. For those who don't like it, just the sight of a used porridge pan soaking in the sink, just the smell of simmering oatmeal, just the sound of it spitting and belching as it cooks and just the associations of the word "claggy" are enough to induce a state of trembling fear. If you are one of these people, don't read on.

If you are afeared of the clotting properties of the usual kind of porridge, it won't cheer you to know that Scottish shepherds traditionally made their porridge once a week only, pouring it into a draw to set to a gelatinous firmness. Each day, they would cut off a slice or two of this grey mass to take with them to work. Glasgow factory workers used to do the same thing. Annette Hope's A Caledonian Feast, a splendid culinary history just reissued by Canongate (£9.99), contains these and many other details about "parritch", or "them" as it is traditionally called in Scotland. The English have often "mocked the Scots' dependence on oats" - Dr Johnson famously defined oats as a "food given in England to horses and in Scotland to men" - but Hope defends the rugged versatility of this grain, in haggis, herrings and oatcakes, as well as porridge. She even argues that "cold porridge, disagreeable as it sounds, is actually not unpalatable if carefully made and well salted; it has satisfactory rib-sticking qualities which sustain one until the next meal, even if that is many hours away". This information will probably not win over the unconverted.

There are many strange rules associated with this warming food. Scottish porridge should be made rather like polenta, poured evenly into boiling water with the left hand, as the right hand stirs, clockwise, with a special stick known either as a spurtle or a theevil. The only ingredients should be water, oatmeal and salt, with a little milk or cream poured over to cool the mouth while eating. Once cooked, it, or "they", is eaten standing up, for which Hope offers three competing explanations: "1. It allows the eaters to remain alert in the event of a surprise attack" (the Braveheart explanation). "2. 'A stauning sack fills the fu'est'"(whatever that means). And "3. Porridge is more easily digested this way. Anyone who has had porridge in bed will corroborate this". To which porridge-haters might reply that any food that can only be digested standing up is very sinister indeed.

Personally, I love porridge, though I make a very pampered English version of it, with jumbo oatflakes. True porridge should be made with real oatmeal, either rough, medium or pinhead, and takes up to half an hour to cook to the requisite softness. So-called porridge oats, oatflakes or rolled oats, were developed in America by the Quaker Oats Company in 1877. The oatmeal is pre-steamed and rolled, which greatly cuts down on the cooking time but also can make the finished porridge reminiscent of wallpaper paste. Jumbo oatflakes, which have also been pre-steamed, are better because they are made by rolling the whole groat, resulting in a much nuttier, more satisfying texture.

My porridge, without which I could barely rise on winter mornings, is also un-Scottish because I cook it with two parts milk to one part water and one part oats (about 10 minutes of simmering and stirring), and add no salt, though I do add beads of golden honey to the milky bowl as I eat it. To many a Scot, this would seem suspiciously indulgent.

This version is less rich, however, than the porridge made by the Norfolk chef Galton Blackiston, as described in his book, Cooking at Morston Hall (Navigator Guides, £17.95). Here, the oats are soaked overnight in milk, and cooked slowly in nothing but milk and butter, with cream poured over on serving. Utterly delicious - if you don't detest porridge, that is.