The pernickety young should learn the joys of cut-price eating

What lengths would you go to in frenzied pursuit of a smaller supermarket bill? I pushed the boundaries of decency on the eve of the Coronation by keeping the long-suffering staff of Wimbledon’s Waitrose waiting 10 minutes at closing time as I attempted – and kept failing – to download the chain’s shopping app. Why? Because a friend had just told me their “Fish Friday” offer granted a 25 per cent discount on piscine delicacies, meaning I could knock a tenner off my celebratory buffet.

So, when I read that an increasing number of shoppers were buying “yellow sticker” discounted groceries (two fifths of households last month, according to data from Barclays) I thought, “Why so late to the penny-pinching party?” I never buy anything at full cost if it’s sitting next to a cheaper, wizened version that’s just hours away from a “do not resuscitate” order.

The Food Standards Agency has warned that cost-conscious shoppers may put their health at risk by consuming “spoilt” food. Well, yes, they might if they place their purchases in a humid spot for weeks and let them bloom with mould. But the British public aren’t blithering idiots; we know you should eat not-so-fresh sea bass before you turn to those miracles of longevity that are a decent box of eggs.

I don’t want to boast, but I once made a delicious omelette from a box of Burford Browns that had been sitting in my fridge seven weeks beyond the sell-by date – and my entire family survived the experience. But then I was raised by a war-baby mother who hoarded tins of Harold Wilson era Bird’s Custard Powder (bulk bought to survive the three-day week) well into the late 1980s. Wasting food was a grievous sin, second only to keeping the radiators on past March.

But, for me, the patron saint of thrifty groceries was the late British beat poet Michael Horovitz, whom I met when working on a magazine in Soho in the early 1990s. Although his methodology was really pleading and scavenging, not shopping. The writer chatted up staff in the West End branch of Cranks – the seminal health-food chain – and would drop by at closing time to claim the day’s last loaves and sandwiches free, as a form of artistic patronage.

He had similar arrangements with a couple of Italian cafés and would wander by my office later to share his spoils. This first alerted me to the glorious fact that the cheapest time to shop, if you don’t mind lack of choice, is two minutes before the doors are locked. Only last week I bought six delectable pastries from a posh deli for a fiver (full price £18) because the assistant was so keen to evict me. Meanwhile, squeezed-middle sushi lovers will be aware that Itsu sells off all its remaining wares for half-price half an hour before closing.

There are limits, of course, to this vigorous parsimony. I once dipped my hand into an open packet of Alpen in my uncle’s Pimlico flat and consumed a stale mouthful before I noticed it was heaving with larvae, and my late mother-in-law offered me some Carr’s water biscuits that were older than Nefertiti and crumbled to air in my hand. But nurturing healthy scepticism round sell-by dates is a skill worth instilling in the pernickety young who seem to think you can catch botulism from a refrigerated, week-old lasagne.

We should emulate French matrons at a farmer’s market: pinching the produce to see what life’s left in it, then haggling for a cutthroat deal. The benefits are obvious: less waste and everything tastes sweeter when you don’t need to rob a bank to afford it.