London
There are many signs of the city's economic boom: ever-rising house prices; down and outs grumbling that a GBP1 (HK$16) handout won't even buy them a cappuccino; record sales for art - any art, even graffiti; new galleries opening almost daily; the average restaurant meal for one costing GBP39; the rental value of designer shopping streets overtaking New York's Fifth Avenue; and, of course, year after year of record-breaking city bonuses.
But when does economic boom turn into an unsustainable bubble? When house prices move beyond the reach of ordinary Londoners? That happened long ago. Or when building societies or banks crash? Nearly happened last month.
When your local convenience store on the council estate starts selling GBP15 bottles of Sancerre [wine], with a screw top? It's been selling it for weeks. Perhaps such definitions are best left with economists. Or hoteliers, perhaps.
The venerable hotel Claridges may just have redefined 'economic bubble', and rather fittingly through offering an absurdly expensive array of mineral water. Alongside its wine list, the hotel is offering a water list, with 30 top brands from around the world - from Newfoundland to New Zealand, from India to Hawaii via Holland. And the priciest is but a snip at GBP50 a litre.
Yes, 420 Volcanic, apparently the king of all waters, 'with a pleasant smooth sensation on the palate' according to the manufacturers; brought from its source at the Tai Tapu volcano in New Zealand.
If that doesn't suit your palate, or your wallet, diners can try the Mahalo Deep Sea Water, from Kailua-Kona in Hawaii. Much, much cheaper at GBP28 a litre.