Similar trends are recorded in the Asia Pacific region; a 2010 study by MasterCard Worldwide showed that 35 per cent of small and medium businesses throughout the region are now run by women, with annual average growth rates running from eight to 42 per cent depending on the country.

This masculine look 'signals a turn towards seriousness and no-nonsense professionalism, and not just at work', says Constance Dunn, author of the 2010 style book Practical Glamour. 'Women in all spheres have had to rethink and re-evaluate their lives, futures and most fundamental attitudes.' Dunn says that the lacklustre global economics of the past few years has had a lot to do with the trend; women now have to be even more conscious about their appearance when competing for jobs in a restricted market.

'The use of masculine fabrics, subdued colours and prints, classic silhouettes and few details - such as frills, bows or lace - signal a 'let's get serious' shift that is being felt by all women,' she says. 'The power dressing trend is a logical response to the need felt by women to shorten the reins and exert more control over our destinies.'

Any social undercurrent aside, however, women still want to look beautiful, elegant and even sexy, while wearing the stronger, harder-edged clothing. Susanna Forest, owner of the Susanna Beverly Hills boutique, has made a 35-plus year career out of dressing powerful women; she regularly sends tailored suits to US Secretary of State Hillary Rodham Clinton, and has outfitted the likes of singer Barbra Streisand. Sheikha Moza, the Queen of Qatar who has been listed by Forbes magazine as one of the world's most powerful women and has graced Vanity Fair's recent best-dressed list, is a customer.

'I call it the heels-and-skirt look,' says Forest. 'It's for women who deal with men every day, who have to still be feminine and elegant, who have a lot of class.'

Forest's signature look involves sculpted jackets, strong shoulders, a perfect fit. Pants are lean and skirts skim the knee; both are paired with high heels. She has always relied on substantial fabrics - tweeds, fine wool, cashmere, delicate silk for blouses. For autumn, there are fitted dresses with upturned collars, and a tailored black dress with matching coat. She says the new emphasis on this much more polished way of dressing has a lot to do with the world's two latest - and most elegant - royals: the Duchess of Cambridge, aka Kate Middleton, and Princess Charlene of Monaco.

'I have women coming in here with pictures of these royals on their BlackBerries, telling me that's what they want to dress like,' says Forest. 'It's even more important now. These past few years people couldn't find jobs. So women are creating their own businesses, and learning how to look successful.'

In Hong Kong, that power-player aesthetic has long been popular, with women - whether focused on careers or not - typically preferring a Chanel boucle suit and taupe pumps over a floaty skirt and peasant shirt. That perennially soignee and uber-polished appearance is a hallmark of the ladies-who-lunch set. Hong Kong stylist Tina Leung, who has styled the likes of billionaire Pansy Ho and socialite and entrepreneur Michelle Li, agrees that 'power dressing has never really gone away and has always been especially prevalent in some careers, such as lawyers'. But, she adds, there is a heightened masculinity in current collections.

'I try not to follow trends too much, but just add a dash here and there if they're comfortable with it,' she says. 'I'd look for a well-cut blazer with a strong shoulder and a nipped-in waist. This would fit women of all sizes and occupations. A blazer thrown over practically anything adds masculinity.'

Indeed, there is a certain 'look' in traditional power dressing that veers towards the conservative: many of Clinton's pantsuits are a case in point, although the infusion of pastel colours, or a slight ruffle at the neck from a blouse can help soften the overall aesthetic. But politically powerful women have come to have their own trademarks, and their choice of clothing often inspires much water-cooler chatter. Former first lady Laura Bush was uninspiring in her choice of twinsets and pearls while former Alaska governor Sarah Palin - who may or may not be running for president next year, but acts as if she is - has an edgier repertoire that has included sleek leather jackets, high-heels, lip gloss and that famous twisted updo. Her rival, Congresswoman Michele Bachmann of Minnesota, who announced her candidacy for president while wearing an appropriately elegant silvery grey suit, has said that her style is derived from the likes of Jackie Onassis and Audrey Hepburn; she is always immaculately dressed, with glossy hair and flawless make-up.

Michelle Obama was anointed style icon after her husband got the top job, and somehow manages to look suitably imposing while in something from J. Crew or fashion wunderkind Jason Wu. Managing director of the IMF, Christine Lagarde, is a fan of Chanel and has an instinct for accessorising - two factors that helped land her on the Vanity Fair list (which was, of course, topped by the inimitable French first lady, Carla Bruni-Sarkozy.)

And the image of Wendi Deng Murdoch, in a fitted rose pink blazer, whacking the man who shoved a pie in the face of husband Rupert, is seared into the public's mind.

'I think interesting examples of the new power dressing strongly reflect the influence of pop culture and shows like Mad Men,' says Lesley Scott, fashion critic and editor-in-chief of fashiontribes.com, a popular fashion blog.

'Designers have incorporated the extremely feminine vibe of the way women dressed during that period, but are now making proper sheath dresses and elegant wide-legged trousers from really fine menswear-suiting fabrics - a new millennium fashion battle of the sexes, if you will.'

Of course, as with any trend, it's all in the wearing. New York stylist Alexander Allen, who has styled celebrities include Beyonce, Shakira and Pink, says that the look isn't for everyone, although there are certain components from it that should work in most wardrobes.

'For a power pant or skirt suit, the ideal person would be fairly statuesque, slim and have an edgy attitude to pull it off,' he says.

'It's best paired with a slick patent leather stiletto pump, sans jewellery, a sleek hairstyle and bare to dark tone make-up.' He advises monochromes, but suggests a button-down shirt in white for contrast, or pairing a wide-legged pant with a feminine top. A deep burgundy or purple lipstick, or perhaps some large diamond stud earrings, can add flair.

'The easiest advice that I could provide is making sure the key pieces - structured blazer, knee-length skirt, wide-legged trousers, and an edgy stiletto pump - are in gray, gunmetal, midnight blue, or black,' he says.

But there is one essential factor: 'One's attitude and confidence to exude this powerful feeling are needed to create and enhance the swagger,' he says.