Blaze a trail: Why jackets are required this season

With power dressing such a key theme for the season, it's hardly surprising that the jacket is back.

After all, Alexis Colby would hardly have made grown millionaires tremble in a nice comfy cardigan. The jacket has well and truly come out of the office to add instant structure and edge to anything from a flimsy party dress to a pair of distressed jeans, and there is a style to suit everyone.

The boyfriend jacket– namely a slightly oversized, androgynous style, as seen at Stella McCartney and Alexander Wang – has been back on the scene for a few seasons now, and has gone from wardrobe statement to wardrobe staple. Find a flattering one and you'll wonder how you ever got dressed without it. Jane Shepherdson, the chief executive of Whistles and a firm jacket fan, explains their appeal thus; "Long-line blazers and boyfriend-style jackets can add effortless cool and a boyish edge to even the most feminine look and can morph from smart to casual. As soon as you slip it on, you feel structured and ready for anything – it's like fashion armour!" Putting on a well-tailored jacket really can impart instant confidence – possibly even a satisfying megalomania.

However, if you are less interested in conveying authority than a wild-child disregard for it, the biker jacket is for you. Black leather, as seen at YSL and Balmain, is the most obvious way to channel the early Nineties grunge-inspired look (think Kate Moss arm-in-arm with a hotel-trashing Johnny Depp) but grey or olive are also good. A longer line adds a new twist to the theme – Whistles' hip-length biker is a fashion-pack lust-have with a waiting list, but anything Seventies-style and brown à la Starsky and Hutch should go back in storage. Bikers don't have to be leather, though: Zara has a great black suede style; Acne's Kermit-green suede version feels fresh and will ensure that grunge doesn't tip into goth. If you can't afford leather don't go down the dreaded synthetic "pleather" route; try a black denim version instead, such as the one at Warehouse. Wear all of the above with skinny jeans, slender chinos, leggings and long T-shirts, draped or ultra-girly dresses, basically; anything except leather leggings or trousers, unless you want to be mistaken for the back seat of a minicab.

For a softer, quieter effect, fitted jackets with a draped front, as pioneered by Rick Owens, are perfect. Look for fine, pliable leather (not the thick, creaky type) or floppy fabric, and wear with a simple shape underneath. The biggest statement of all comes from the trophy jacket, distinguished by its arresting detailing or exaggerated shoulders. The trend was around last season, with the charge led by Balmain, but it's taken the high street by storm for autumn where it's a case of "pimp my jacket". Embrace excessive embellishment in the form of sequins, huge shoulder pads, lurex fabrics, tuxedo detailing, shine, studs and rivets, but, to avoid looking like Ivana Trump circa 1985, dress the look down with skinny jeans.