To describe the look of a particular decade as a seasonal trend now feels almost irrelevant. These days, thanks to vintage-loving celebrities, it is, perversely, more fashionable to occasionally ignore contemporary catwalk creations and their high-street spawn and plump instead for something from a previous decade – or at least to combine the two.
Mid-century fashions – the 1950s and 1960s in particular – have proved a favourite, whether you're committed to your rockabilly styling à la Winehouse, or merely dipping a toe in the waters of old-school glamour in the manner of any actress gracing a red carpet secretly thinking she is Elizabeth Taylor.
Nevertheless, though looks from those decades have been happily swirling just beneath the surface of mainstream fashion for several years now, this autumn what started as an undercurrent looks set to build to tidal-wave proportions.
On the Prada catwalk, which can usually be relied upon to define the mood of the ' season, there were demure housewives straight out of the late 1950s and early 1960s, wearing their hemlines low and their necklines high – and somehow all the more alluring for it. At Louis Vuitton, Marc Jacobs was thinking along similar chronological lines with wasp waists and circle skirts.
As if there weren't enough inspiration on the runways, a new season of TV drama Mad Men, set in the same period, has just begun in the US. Although it's not being shown in the UK until next year, its small-screen Stateside premiere sent the British media into a frenzy, providing us with ample visual references in the hyper-womanly forms of Betty Draper and Joan Holloway.
Although the high street will be awash with copycat pieces, the obvious course of action – if you are after a slice of authentic mid-century chic – is to rake through the rails of your nearest vintage emporium. With dedicated concessions in stores such as Topshop and – for rare, designer finds – Harvey Nichols, getting your hands on the originals no longer involves the insider knowledge and legwork it once did (although you'll pay a premium for that convenience).
But despite its current popularity, buying and wearing vintage remains a tricky business. After you've laid your hands on the perfect piece, there's the question of size. Take it from me, there is no greater sartorial disappointment than finding your dream dress only to realise it is never going to fit; I once stood on the shop floor of King's Road institution Steinberg & Tolkien – now sadly closed – seriously considering the removal of a rib as two assistants valiantly tussled to close the zip on an Ossie Clark maxi.
Eliisa Makin, stylist for The Independent who also runs personal styling service The Wardrobe Consultant, recommends finding yourself a reliable alteration service: "Comparatively few of us have good enough sewing skills to alter clothes ourselves," she says. "But a lot of people forget that you can get things altered and even entirely remodelled. If something is far too small there's not a lot you can do, but pieces that are too big or just a little off the mark can be given a new lease of life if you find a good tailor."
Added to the question of fit, is the equally thorny question of age – of the wearer, not the clothing. A slightly threadbare 1950s prom dress will look romantic and whimsical on the very young. But, frankly, the same item on someone who remembers, or nearly remembers, that decade, has the potential for shades of Whatever Happened to Baby Jane?.
The answer to both of these problems, according to Karen Proctor, founder of London bespoke dressmaking service Albertine Burdett, lies in a return to the practices and values that produced the kind of clothes we salivate over in Mad Men.
"We like to think we have more choice when it comes to what we wear these days because we have more shops," says Proctor, a former personal stylist at Liberty. "But, actually, that translates to far less. In the 1950s it was normal to go to your dressmaker, where you'd choose your pattern, tweak it to suit, then choose a fabric that was right for your skin tone and appropriate for whatever you were going to wear it for. So you'd end up with exactly what you wanted, fitting perfectly and with no chance of bumping into a woman in an identical dress."
Proctor founded her business three years ago in that spirit of 1950s demi-couture. She offers a range of 15 designs, all inspired by classic silhouettes. "Grace" is a sweet, flippy sundress in which it's easy to imagine Ms Kelly wandering in Monte Carlo's old town, while "Greta" is a body-hugging bombshell shift and "Gwendolyn" the classic prom style.
Clients make an appointment to try on samples of the styles while Proctor advises on design adjustments to flatter their shape, but the real fun comes with choosing a fabric. Proctor can source pretty much anything, from rare vintage American cottons to sumptuous new material sold off by the couture arm of top design houses such as Chanel and Armani. The dresses are then made up by an ex-Savile Row tailor before a final fitting to ensure it's perfectly sized.
The end result might be deliberately faithful to the 1950s or just give it a passing nod: "A lot of my clients don't want to be wearing the 1950s 'look'," explains Proctor. "If you want a dress for a corporate function or a formal event, then looking too period isn't right. So all the dresses have been subtly updated – the waists have been dropped slightly, the necklines are a little lower and we've tried to make dresses that give a structured silhouette without the need for constricting underwear. You have to remember that vintage 1950s dresses were designed to be worn with boned underwear."
Proctor offers a highly personal service, with many repeat clients who have bought the entire collection several times over in different fabrics. She'll even make a note of any big occasion you intend to wear your dress to in case another client is intending to wear a similar style at the same event.
"There used to be a distinct culture around the visit to the dressmaker and the creation of a dress and it was that process, as well as the clothes, I was inspired by," says Proctor. Counter-intuitive as it may seem, if you want the genuine article, you could do worse than start entirely from scratch.