We make our homes look smarter and glossier while, inside, families become more divided and dysfunctional

I live in Earl's Court, where for the past week the usual traffic of down-and-outs has been jostling with Saab-loads of the up-and-coming. Nest-builders from Newbury and housewives from Hull have descended upon west London for the Ideal Home Exhibition, an annual home-improvement extravaganza that offers model rooms and perfect living spaces. Sponsored by the Daily Mail, the apostle of the ideal family, the exhibition is stuff full of faux marble, stripped pine and gilt taps - all the amenities, in short, for a perfect DIY lifestyle.

The trappings of the ideal home are not confined to Earl's Court or the pages of the Daily Mail. Watch television, scan the newsagents' shelves or leaf through the Sunday supplements and you'll find yourself immersed in home-improvement tips. "How to decorate your children's room in a weekend!"; "Ten steps to a new garden shed"; "Plump a pillow and revolutionise your lounge!": the happy homemakers' bibles urge you to take up the paintbrush, the saw and the steel wool to transform your life into a lifestyle.

Judging from the numbers of these how-to manuals, and the multitudes who regularly pack Ikea, Habitat and Heal's, interior design is our new national pastime and the search for the perfect terracotta red our common mission.

Chief cheerleader of this new sport is Laurence Llewellyn-Bowen, a Byron-locked, tight-trousered designer, whose uncanny resemblance to our glorious PM has lent his show, Changing Rooms, the gravitas of Prime Minister's Question Time, and his tips the status of government directives.

Laurence shares Tony's gung-ho enthusiasm for prescriptions and his predilection for fifties-style conformity. He is as happy to issue pointers about the perfect home as his doppelganger once was to issue guidelines for the perfect family.

Fixing a house is a lot easier than fixing a family: Laurence need only prance round an indifferent interior and tell us how to lay down tiles and base-coat the walls. Tony had to take on the rather more onerous duty of assessing the damage done to a traditional institution by new trends and "lifestyles", and then telling us how much money he was ready to give us per child, how big a tax break he was going to offer each family, and when exactly an informal partnership was entitled to be considered a bona fide union.

Alas, their physical resemblance has served to underscore how dramatically different the performance ratings of the two bright-eyed, bushy-tailed Mr Fix-its have been. While Laurence has entered the nation's bloodstream as well as its front doors, turning ordinary terrace houses into Habitat havens, Tony and his home improvement team have failed to make over our shabby home life. Nurseries to ease the burden of working mums; tax breaks to support married couples; help for single parents - these were among the tips that could have improved family lives or at least renewed the tired fabric of marriage. Tony and his team, though, got only as far as taking out the paintbrushes and pouring the emulsion in their pails. Then they put up their feet for a tea break.

Houses up and down the land are looking spruce and smart, newly coated with perfectly mixed emulsion, brightly finished with scumble glaze. The families within, however, grow ever more dysfunctional, divided and destroyed. No masking tape can fix these cracks, no gloss camouflage these dents.

Our obsession with home improvement tells us that we are still yearning for that old-fashioned concept - the hearth. Today, though, the hearth has been reduced from a symbol of cosy domesticity to a faux marble reality, where a gas fire crackles merrily above simulated logs.