Last Friday night, all but three tables at the sardine-packed Fifteen restaurant in Watergate Bay, Cornwall, were drinking clear, sweet-tasting water served in handsome, functional jugs. And at Soho's antipodean Flat White café, stainless steel jugs line up on the counter allowing you to democratically help yourself.

Only at Queensway's Mandarin Kitchen did a waiter respond to my request for tap water with an expression caught somewhere between surprise and horror. Two very plain glasses were eventually brought, only to be ignored for the rest of the night.

A lot of the credit for the swing to tap should go to Giles Coren, restaurant critic for The Times, who started his own vendetta against bottled water in January 2007. So in tune with the zeitgeist was he, that the cause was recently taken up by the Evening Standard's "Water On Tap" campaign - with no acknowledgement to Coren, mind you.

But I think we need to take it further. The next step, surely, is for restaurants to purify and even carbonate their own water on the premises, as at the organically minded Duke of Cambridge pub in Islington, in order to eliminate "water miles" and minimise glass wastage. To all those restaurateurs who can see their water profits going down the drain – this could be the answer. Offer your own lightly chilled filtered water, still or sparkling, and you can charge us something for it. (The Duke charges £2.50 bottle).

It's not just a cost issue. It's not just a food miles issue, although it does seem hideous to fly bottles of water around for one half of the world when the other half is walking half a day to the local spring. It is, I think, just a common sense issue. If you live in a place where the tap water is drinkable, then drink the tap water.

If you occasionally need a sparkle, perhaps at lunchtime when a glass of water often becomes a substitute for wine, then order it and enjoy it. Just try to make sure it is British, or from a carbon-neutral company such as Belu.

The main thing that Coren has achieved is to give us a real alternative to that rather expensive question "still or sparkling?" Personally, I think we all owe him a drink.