'I'm struggling,' Daphne says. Four mackerel corpses lie on a board. Neither of them likes mackerel - oily, dark fish with tough raincoat skins - but Daphne feels obliged to buy them once in a while because they are plentiful, cheap and - so all the cookbooks say - nutritious, full of life-giving oils and omega fats.

'You have to remove the backbone and then sort of dust them with flour before lightly pan-frying them.'

'Do you want me to help?'

'Please. It says how to fillet them on page 21, but ...' He looks at he recipe. The picture shows the fish lying neatly on a plate, crisp, decorated with a small, casually composed salad of rocket, with a glistening mound of gooseberry sauce and a generous - not too refined - lemon wedge next to it.

'I couldn't get gooseberries but luckily we have a jar of lingonberries that we got in Sweden. '

'That was six years ago. '

'Do you think they will have gone off?'

'Everything goes off.'

He sharpens the knives and cuts off the heads and tries to remove the backbone. The flesh of the mackerel is bloody. When he finally pulls the backbone free, what 's left of the fish looks like a swab from an operating theatre.

Daphne has opened the lingonberry sauce. 'It 's a little crystallised around the top, but deep down it looks all right.'

'Fine. Let 's have diced mackerel chunks with crystallised lingonberries and while we are at it why don 't we see if we can find those Italian artichokes in oil which we have been keeping since 1979 for a special occasion. We'll just throw them casually around the plate, à la Rick.'

He stares at her. His head is bulging from the inside against the walls.

'Do you mind if I bin these fishy remains?'

'You're not cross are you?'

'No, why should I be? Shall we forget about mackerel for ever? We don't like them and they make the place stink.' (From Justin Cartwright's new novel, The Promise of Happiness.)

The British have always been a little equivocal about fish. It's one thing to eat a neatly cooked piece of halibut in a restaurant, but quite another to have to grill it at home. And worse still, to have to fillet or clean it. My parents' generation only ate white fish or salmon. Anything dark or oily was considered a minority taste, and the minorities in question were usually swarthy people from the Mediterranean who would eat anything.

This prejudice towards fish has by no means vanished. A few years ago, in North Wales, I asked a fisherman what fish he ate, hoping for a little folkloric chat, and he said, 'Birdseye fishfingers.' There wasn't a fish shop for miles, although the local supermarket was full of breaded plaice and battered scampi.

Personally, I think fish and chips are an attempt to make fish taste as little like fish as possible. A few fish are still described, approvingly, as tasting just like chicken, tuna in a can being the leading contender. Oddly enough, sushi restaurants in this country now have very little sushi on the conveyor belt for the same reason: it tastes too much like fish. Instead, California rolls, crème brûlée and yakitori far outnumber the plates of sushi or sashimi.

It was all part of the myth of empire, that foreigners had to eat the unmentionable parts of fish, flesh and fowl because they couldn't get - or afford - the good stuff. In South Africa, where I was born, octopus was used for bait. It hadn't yet been anointed as calamari. When I arrived in Britain in the late Sixties, sprats were given exclusively to cats, and people like my father ate whitebait and Dublin Bay prawns, which, it turned out, were made from monkfish, a fish so ugly it could not be seen in public or sold except under an alias. Now, of course, monkfish is a sort of aristocrat of fish.

The idea of food as a form of self-expression or lifestyle, is relatively new. Food used to be an expression of unchanging depend- ability. A friend of mine once said that his mother 's only criterion for judging a restaurant was the state of the plates: hot plates indicated a certain class. I once tried to explain to my own mother that in Italy they ate meat tepid. 'They would, ' she said, sadly. Not being able to get the meat - or even the plates - hot was a sign of national degeneracy, like Mussolini having one for- ward and three reverse gears in his tanks.

The other thing which formed the British national character was the Sunday Roast. It wasn't just that no other country knew how to carve it or cook it properly - with plenty of lard - but that they mucked about with their food to hide its taste because it was of inferior quality. Garlic was really just a way of disguising putrefaction. The other thing that foreigners couldn't do was gravy. They added wine and herbs, rather than cornflour. Strangely, this sort of lingering prejudice is understood by shrewd restaurateurs to this day - fishcakes, anything cooked with bacon and nursery puddings are always available in sophisticated places like the Ivy. Its by-product, the Wolseley, has chips wrapped in paper - good quality paper, neatly folded, but still chips.

When I left university, vaguely aware that things were moving on, I found Elizabeth David and tried to make boeuf bourguignon and daubes without success. Wine in cooking seemed wonderfully louche. In South Africa we had our own version:we poured Lion lager on the barbecue if it was too hot, something only men were qualified to do. Women dealt with salads. Cremating meat was men's work.

It seems obvious that food, and fashions in food, are barometers of national self- regard. The French, for example, have a high self-regard, and so their restaurants haven't changed much in 30 years. I had a meal on the Left Bank in Paris a few months ago that I could just as well have eaten in 1969: leeks vinaigrette followed by daube of beef, îles flottantes and cheese.

Britain, by contrast, is plagued by self-doubt and prey to the urge for sensation. No metropolitian restaurant has put prawn cocktail and chicken Kiev on the menu for years, except in a spirit of irony.

Here, fusion and novelty rule: the loin must lie down with the lime.

· The Promise of Happiness by Justin Cartwright is published by Bloomsbury at £16.99. To order a copy for £14.99 plus UK p&p, call the Observer Book Service on 0870 836 0885.