WITH supermarket retailing trends inexorably shifting towards an open-all-hours trading, British supermarket chain Sainsbury this week heralded the arrival of the all-night supermarket shopping experience shop-till-you-drop, or at least until the arms of Morpheus can be no longer denied. From the end of this month a limited number of stores will stay open from 8 a.m. on Friday to 10 p.m. on Saturday, a 38-hour trading weekend.

Sainsbury says the move is in response to demand from what the people watchers in market research have inventively bar coded as "Big Dippers, Elastics and Desperadoes", not high spending, insomniac pop groups, but sociological categories of people who want or need to shop late. Desperadoes comprise the biggest group, single men who lack the modicum of advance planning to keep their fridge stocked with the basic essentials. The second group, elastics, comprise customers obliged to shop at odd hours on their way home from work. Big dippers have no set main shopping day, preferring to dip into the supermarket several times a week, including the early hours of the morning.

As yet no Irish operator has grasped this particular nettle, but with the Safeway/Fitzwilton combo likely to cut the cake of market share even finer, it is probably only a matter of time before the bleep of bar codes disturbs the suburban silence in the wee small hours.