The idea of peeling off the cashmere and heat-tech to try on a bikini or a beach kaftan right now is enough to make us all come out in goose-bumps. But if you are among the 11 million Brits estimated by a recent Halifax survey to be taking a winter-sun holiday between now and March, the current Siberian-style temperatures are unlikely to deter you from heading to the shops to scoop up some new swim and beachwear.

And even though the ice on the windscreen may be thicker than Nigella's Christmas-cake icing, and your lawn resembles the Arctic tundra, be assured, there is plenty of swim- and beachwear in stock right now to tempt you into some new poolside purchases.

Lingerie specialists, including Rigby & Peller with branches across the UK, and local specialists like Pretty Things (Cockfosters and Buckhurst Hill); Leiberg's (Temple Fortune); Fit to Bust (Leeds); Bal Harbour (Prestwich) and Cricket (Liverpool), maintain a year-round cache of swimwear and cover-ups, as do the better department stores.

John Lewis branches have a small year round collection, including at Oxford Street, Brent Cross and the Trafford Centre, while Fenwick, Brent Cross is known across North London for its year-round stash of swim- and beachwear. Currently, brands include the fabulous Meghan Fabulous, Pour Moi, Fantasie and Gideon Oberson, as well as beachwear from Lamis Khamis, Gia and Halle Bob. The store also has Havianas in - among other colours - pink, gold and silver, at £19, and metallic mules in silver and gold at £15.

Fenwick, Bond Street has just received a fresh delivery of beach and swimwear, perfectly timed for those jetting off to the sun. Brands include Eres, Melissa Odabash, Vitamin, Missoni and the clever, body-shaping Miraclesuit. The store also has Heidi Klein's nicely nautical navy-and-white stripe Riviera collection and her brown/tan animal print bikini and maxi dress, as well as cover-ups in gauzy, lightweight cotton, trimmed with gold sequins, from American designer Debbie Katz.

Some of the most fashion forward one-pieces are, in fact, the most retro, thanks to the highly contagious 1950s Mad Men trend, which has infected swimwear almost as profoundly as the rest of fashion. The trend has manifested itself in sweetheart necklines, draping, shorts-cut legs and even some "skirts". Mad Men-inspired two-pieces tend to be itsy-bitsy, with a distinctly Bardot-esque feel, with lashings of frills and spots.

While the long-established fashion rule that says "if you wore it last time around, you can't wear it again" is generally defunct - a good thing, as no woman over 40 would otherwise have anything to wear - in the case of 1950s/early 1960s swimwear, the rule should be observed; this is one trend that should definitely be reserved for the young and lithe of limb.

Another key trend that has spilled over from mainstream fashion is asymmetry. The one-shoulder swimsuit has been around for a couple of seasons now, but - weird tan marks aside - remains eminently embraceable since, by elongating all but the roundest of figures, it is almost miraculously flattering. The genius of Alber Elbaz seemingly knows no bounds; his swimwear collection for Lanvin includes, as well as a low-key black ruffled baby at a mere £330, a searingly bright fuchsia asymmetric one-piece that is almost too chic for the beach.

In one sense, trends are slightly irrelevant in swimwear. Unless you have a body like Gisela Bundchen, you should keep fashion in mind, but make your final selection based on what most flatters your shape.

Philippa Bradley, who has been importing up-scale swimwear and lingerie for 35 years, including brands such as Princesse Tam Tam, Eberjey and Laurence Tavernier, has some wise words on ensuring your bikini or swimsuit provides optimum figure enhancement: "This season's fashion forward fabrics, such as stretch satin, add glamour to the traditional one piece and are perfect for camouflaging a 'tummy'.

"As ever, a tie-sided bikini cleverly elongates the leg and narrows the hips. If you are lacking cleavage, keep the look fresh and young in a simple triangle-shape bikini top with added frill detail, or try a bandeau shape. For a bit of extra lift, look for moulded cups. And if you need a bit more support, many styles have an underwired option."

And counter-intuitively, notes Bradley, "bold prints and patterns take the focus away from lumps and bumps".