Other colour combinations sink without trace but dark blue and white sail on, writes Marion Hume
In fashion, most things change, but a few stay the same. The appeal of navy and white as a combination for summer has stayed fresh while other ideas have long since wilted.

The colour duo has been around ever since the Navy first wore navy, in the 18th century. Women first fell in love with perky combinations of blue and white around the time they first became bathing belles at the beginning of this century; sketches of summer fashions from 1903 show demure maids, covered to their knees, entering the British briney in the same combination of colours seen in many a beachwear collection today, (although there was rather more to them in those days).

Gabrielle "Coco" Chanel deserves a mention here. Her lover, Boy Capel, set her up in a hat shop in Deauville in 1913, just as the Normandy town was becoming the smart watering hole on the "Cote Fleurie". Long before she designed the little tweed suits that became her signature, Chanel was wearing fluid floaty layers of crisp white or cream, trimmed with dark blue. Since then blue and white has never been out of style.

This summer, it is easier to name a designer or a designer-led retailer who has not included navy and white in its seasonal offering than it is to list those who do. Although the pervasive colours now in the shops seem better suited to ice-creams than clothes, smart navy and white outfits can be found everywhere from Joseph to Jigsaw. At designer level, Dolce & Gabbana's offering has the right kind of fresh breeze to it to make one think of balmy summers , even if we don't appear to be experiencing one.

So why is navy and white one of fashion's never-ending stories? Perhaps because pure white is given a touch of gravitas when matched with serious navy? Because masculine navy is feminised by white? Because we would all much rather be at sea, wearing nothing but deck shoes, white shorts and a navy polo shirt, than be at work? Or it is simply because lots of grown women can't stand pink or florals, or pale pistachio, yet find it just too depressing to wear wintry black all summer long?

Whatever the answer, white and navy is serious business for manufacturers. Somewhere in Italy right now, a group of senior fashion executives at one of those huge textile conglomerates that are scattered across the north are probably sitting down to discuss - just as they did yesterday and, indeed, last year and the year before that - the exact shade of navy that is right for some future summer's offering. For manufacturers take navy in any of its minutely varied shades very seriously.

And because they worry so much, you needn't worry at all. It is virtually impossible to go wrong if you restrict your clothing choices to navy and white. And there aren't many things in the fashion world you can say that about.