Philip Hensher: We are a nation of scandalous food wasters

Around this time of year, the poor food writers of the nation are called upon to supply us all with recipes for "leftovers"; it being generally thought that the orgy of food-buying and preparation over Christmas will leave everyone with great flapping carcasses, mountains of Brussels sprouts and whole Stiltons which otherwise will remain only partly excavated until Eid.

And every year, they rise semi-valiantly to the challenge with "Turkey and Stuffing Pie" (The Times), "Christmas Bird Broth", (this newspaper), or The Guardian's tried-and-tested "Devilled Turkey" and fried Christmas pud.

If that doesn't take your fancy, then thousands of recipe sites on the internet will supply you with some increasingly bizarre ideas. Turkey Crêpes Mornay; Turkey Hollandaise Casserole (I honestly can't see how that would work in any sense); Turkey Cottage Pie (yuk). And some poor soul in Wisconsin is seriously recommending a Turkey Strawberry and Banana Salad.

Reading these recipes is a curiously soothing experience. A substantial number of published recipes are offered not in a spirit of practical help, but rather in a tone of pastoral fantasy, allowing you to dream about a different and a better life. Your kids, rather than whey-faced Gameboy gazers spooning in Pot Noodles, could overnight turn into apple-cheeked darlings clamouring for their mum's spinach-and-walnut bread with home-churned butter.

Of this genre, nothing has quite the idyllic flavour of culinary advice relating to leftovers. You could become the sort of family where nothing is thrown away; where the Christmas Day turkey is served cold on Boxing Day, in a stir-fry on the 27th, curried on the 28th, and the carcass turned into the stock of a nourishing Thai-style soup on the 29th before it's all frozen and used up at leisure. Yeah, right.

The fact is that as a nation, we throw away a quite incredible quantity of food. In some estimates, a third of all food is thrown away, whether by retailers, restaurants or homes. In part, the food we actually buy can't be preserved any longer - a bag of salad will go slimy in two days, where a whole lettuce will remain usable for much longer. The strains of apples which supermarkets sell are no longer good for keeping - in my experience, those ubiquitous Braeburns go soft and woolly within three days.

But in part, it's just our habits, which are affected by the artificial cheapness of food. If a chicken costs £2.50, there isn't much incentive to eat half now, half devilled tomorrow and turn it into stock on Tuesday. You just eat what you want and throw the rest away. I'm sure, this Christmas, nine out of 10 turkeys were in the bin by Boxing Day morning, and a ton of sprouts along with them.

Wasteful and morally deplorable as home disposal is, the scale of supermarket waste is mind-boggling. Supermarkets, under the influence of the "sell-by date", dispose of huge quantities of perfectly good food, either to their staff or to the bins, without a second thought.

Those sell-by dates are, in most cases, arbitrary and nothing at all to do with food safety. I first became aware of this through a bizarre debate over passion fruit in my local Sainsbury's. Now, I like passion fruit a good deal. But whenever I tried to buy any in Sainsbury's, they were glossy and fat as plums. As you know, passion fruit are no good until they are shrivelled and wrinkly. Sainsbury's were not only selling them when they were a good two weeks away from edibility; the sell-by date was also obliging them to throw them away two weeks before you would want to eat them.

Food retailers place almost no value on food which will keep, preferring in many cases - forced fruit, bagged salads - to sell it to us in forms which must enormously increase waste. In the case of food which will keep without any further attention, the sell-by date, which, as every cook ought to know, bears no real relation to edibility, encourages us and, they claim, obliges them to throw away food - cheese is a particular absurdity - with a long useful life in front of it. What end is served, apart from persuading people to buy 50 per cent more food than they actually need, I do not know.

The wastage of food is a morally disgusting spectacle in this country. It can't seriously be addressed by those soul-salving recipes for reusing old roasts, particularly since they tend to be published all of once a year, and relating entirely to the remains of Christmas dinner. Rather, we need to start considering whether the food we buy is realistically going to be eaten during its lifetime; we need to start preferring the sorts of food and strains of fruit - often much nicer ones, anyway - with an extended lifetime. Buy whole fruit and vegetables, not the pre-prepared ones; they'll still be OK in a week's time.

Before we throw anything away, we ought to trust our senses rather than some ridiculous sell-by date; taste those slightly shrivelled mushrooms, sniff at the steak, cut the dried-up end of the cheese off and eat the rest.

Supermarkets are going to go on insisting on their duty to throw away vast quantities of edible food, but we needn't add to this pointless waste.

And since you ask, we didn't have turkey: we had a nice joint of beef, and ate the rest of it cold with pickles a day or two later. One jar of pickles, from the back of the cupboard, was supposed to have been eaten by 2002.

Nobody's died yet.