I once spent a very happy hour in the bins at the back of a Marks & Spencer. A group of freegans — people whose dietary stricture is that they don’t pay — took me along on their regular midnight “bin-diving” foray. In M&S’s well-stocked dumpsters we found unbelievable bounty: roasts and salads, sides of smoked salmon, tiger prawns and lavish ready meals, asparagus, strawberries, cherries, cakes, cheeses, chickens — all in perfect condition. Sell-by dates on most of the food had passed just an hour or so earlier.

We did not find anything that was not perfectly edible. How could we tell? By using those old-fashioned pre-barcode tools, our eyes and noses. When the six of us emptied our rucksacks back in their flat we had nearly £3,000 worth of food. The freegans, all university students, told me that taking up bin-diving had changed their lives. They were richer and they had never eaten so well.

I was there in the cause of journalism, of course, but I did manage to cook a three-course lunch for eight people the next day at a total cost of 40p (I had to buy a couple of onions). Well done, M&S — great food, imaginatively presented: and they hadn't poured bleach or dye in their bins as most supermarkets do.

On Tuesday Hilary Benn, the Environment Minister, announced a government initiative: an end to sell-by and best-before dates, as a way of tackling food waste. “Too many of us are putting things in the bin simply because we’re not sure, we’re confused by the label, or we’re just playing safe.” He’s absolutely right: Wrap, the Government’s waste and recycling agency, says that we throw out more than 220,000 tonnes (£1 billion) of edible food each year while it is still technically in-date — a sizeable amount of the amazing 30 per cent of all the food we buy that is discarded uneaten.

Wrap’s survey tells a depressing story. Fifty three per cent of us would never eat fruit or veg after its best-before date. Thirty six per cent believe best before is the same as “use by”. Half of us don’t understand the different date labels — use by, best before, sell by or display until.

But it’s easy, as ever, to blame ignorant house-spouses for this senseless waste. Another view holds the food industry at least in part to blame. “Sell by and best before don’t do consumers any good at all,” Wrap’s Julia Falcon told me. “They are to do with stock control more than safety, and should never have been visible.”

Supermarkets have to keep the supply of fresh and chilled food rolling through their shelves, because most of such stock is ordered a couple of weeks earlier. “Display until” or “sell by” is no more than a manifestation of the queue of produce waiting in their store rooms. So why, I asked Paul Kelly of Asda, do shops simply not put “display until” in code, and give customers a simple “use by” date?

According to Kelly, there is a gap between health regulation and the demands of the new low-waste economy, which supermarkets have trouble negotiating. “It is a contributing factor to food waste,” he says. “The rules behind sell by are past their shelf life, partly because the technology has moved on.”

Last year Asda did introduce a sensible new labelling system for milk, in response to customers who do their shopping weekly. Now fresh milk has a “use by” date a week beyond its “display until” date, made possible by getting the milk into the shops more quickly. Kelly says that the supermarket would welcome a coherent government reform of the labelling problem. But the fact remains, as Wrap says, that many consumers will still leave a buffer before “use by”.

Another problem is the chilled ready meals of which Britons are so fond (we eat more of them than the rest of Europe put together). Creating sauces to go with meat or fish and vegetables so that they all grow old in concert is a technical balancing act for manufacturers. “And you can’t control what happens outside the shop door,” says one supermarket executive. “How do you know that the customer won’t leave the product in the boot of a hot car for four hours?” So use-by dates on such products are short — which may explain why, according to Wrap’s investigations of our rubbish bins, we throw away around 440,000 ready-made meals every day.

“We have become very reliant on dates on labels, even though we don’t really understand what they mean,” says Falcon. And we’re so frightened of food that we throw it away before we think. So what’s the answer for the busy home cook? Judicious deployment of the nose, taste and eyes, along with use-by dates — it’s time we learnt to trust our senses again.

Bin-diving, I suppose I should point out, is technically both trespass and theft. But it’s terribly satisfying.

alex.renton@thetimes.co.uk

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