THE nagging riddle that has troubled retailers, designers, stylists and fashion-conscious customers everywhere — what precisely do Sting and Trudie do to look so young and idyllically happy together — may never be satisfactorily answered, though to judge from yesterday, watching a Chanel show makes them pretty pleased with life.

While they lovey-doved and Marianne Faithfull took on the role of front-row gooseberry next to them, the rest of us tried to concentrate on the clothes, where another enigma that has been tormenting fashion for several seasons was finally being resolved: skinny or voluminous? Karl Lagerfeld and Alexander McQueen have found a way to incorporate both.

McQueen looked back to the Victorians, with flared skirts, shawl-collared necklines, jackets so slender his models looked like wraiths, and flared skirts — and produced one of his most beautiful collections in a very long time.

The fact that almost every item was a showstopper but also eminently wearable is a mark of how much he has matured since the days when a tartan collection involved political statements about national rape.

McQueen is simply one of the best tailors in the world, with a sensibility that, though very British, works internationally. It works so beautifully in fact, that one could even forgive the unspeakably cheesy finale of his show: the Kate Moss hologram that danced inside a glass pyramid to the theme tune from Schindler’s List. She was wearing a lovely, billowing lilac frock though.

Lagerfeld loves a bit of skinniness in his silhouette too. At Chanel, he cast all of his models in his own image because, frankly, he can. Hair straight as pine needles, bodies encased in black and white, they looked like the beautiful, rich progeny of a Goth-Quaker marriage.

Lower-half slenderness was emphasised with over-the-knee boots in black or white leather and so tight they could double as in-flight, anti-deep vein thrombosis novelty items.

More flattering were the terrific maxi skirts and knitted coats (another emerging trend) that Lagerfeld made sexy and youthful with the simple insertion of long gold zips that were left half done up.

A black wool 60s shift with short sleeves — next winter is all about gloves by the way, and long-sleeved T-shirts you can slip under your short-sleeved statements — epitomised the founding chic-simple principles of Chanel. So did the black and white boucle suits (with above-the-knee skirts) that opened the show, and the beautifully restrained, glossy black cocktail dresses, with horizontal ribbon-bands across the bodice and vertical ribbon pleats in the skirts, that closed it.

They were all worn with a side order of boots and gigantic patent totes. Ultimately, behind every great fashion house is a one-size-fits-all bag.