The notion that the availability of our food is at the mercy of the weather shouldn't really come as a surprise.

Eastern Daily Press: Empty iceberg lettuce shelves at a Tesco store (Picture: PA)Empty iceberg lettuce shelves at a Tesco store (Picture: PA)

For generations, shoppers were perfectly happy to buy fruit and veg during their domestic growing season – unless they were hardy enough to be preserved and stored.

But when a shortage of courgettes and iceberg lettuces is regarded as a 'crisis', it proves just how demanding we have become as consumers, and how reliant our diets now are on global trade.

The fact that we cannot grow leafy salads in this country between December and March is no longer tolerated as an excuse for empty shelves, so supermarkets and wholesalers have built links with suppliers in warmer climes to fill the gap in the UK's growing season.

Of course, those crops are still vulnerable to the snow and frosts which have destroyed Spanish lettuces, prompting rationing, price hikes and panic-buying until an alternate source can be found.

It would seem ridiculous to previous generations that anyone should complain at only being able to buy three iceberg lettuces at a time in the middle of winter.

But perhaps this should serve as a reminder that food is now a global commodity, and however comfortable we have become with the ability to buy our favourite foods all year round, the security of supply will always be vulnerable to changes in markets and the weather – all of which brings the importance of our post-Brexit trade negotiations with Europe and the rest of the world into sharp focus.