FOR Reva Sharma, a typical twentysomething shopaholic, an afternoon at Topshop’s flagship Oxford Street store always starts with a visit to the pick-and-mix sweet counter. Liquorice twists and chocolate brazil nuts provide the energy she needs before serious shopping.

Having stocked up on sweets, Sharma descends two floors. It will take her at least three hours to work her way round the whole store.

Selfridges may be a favourite place to window-shop in London, but if she actually wants to spend money, Sharma goes to Topshop. She is not alone.

For Topshop virgins, the Oxford Street store is staggering: thousands of women, furiously searching for that special item. If it wasn’t a store, Topshop would make a great live theatre. It is a retailing phenomenon, loved by fashionistas and shopaholics, and business is booming. In an average week the chain will sell 33,000 pairs of jeans and 40,000 vests. Thirty pairs of knickers a minute will also be sold.

While other high-street retailers struggle, Topshop is going from strength to strength and has aggressive expansion plans.

Last week Jane Shepherdson, the boss of Topshop, told 1,300 store managers and head-office staff that profits were expected to top a record £100m this year. In the next 12 months the chain hopes to open nearly 1m sq ft of new space. More than 60 cities and towns with the potential for a Topshop have been identified and 35 deals signed. Overseas expansion could follow.

With the backing of Philip Green, the retail entrepreneur who owns Topshop, Shepherdson is about to make life even harder for rival retailers. The expansion plans were greeted with euphoria by her loyal staff. The setting for the annual conference may have been stately — Topshop had put up a circus big top in the grounds of Syon Park, the London home of the Duke of Northumberland — but the event resembled a US presidential rally with lasers, spotlights and huge TV screens. The entire event, fashion show, awards ceremony and a video address from Green, was hosted by Radio 1 DJs Colin Murray and Edith Bowman.

As celebrities in Topshop clothes and tributes from the great and good of the fashion world — including Vogue and Heat magazines — flashed on to the TV screens, Shepherdson announced plans to open major stores in Manchester, Dublin, York and Nottingham.

Green and Shepherdson hope to repeat the success of Oxford Street in Dublin and Manchester. “It is not a store. It is a business in its own right,” Green said. When he needs cheering up he watches as thousands of shoppers pour through the doors. And like the rest of the retail industry, he has needed cheering up as sales at BHS and other Arcadia brands struggled.

Oxford Street employs more than 700 staff to satisfy the hundreds of thousands of shoppers who descend on it every week. Among the celebrity shoppers at Oxford Street are Gwyneth Paltrow, Madonna, Kate Moss, Claudia Schiffer, and Beyoncé.

“When a whole group of us girls come together, we spend hours in the fitting rooms, just trying all kinds of things on: it’s so much fun,” explained Holly Rogers, an 18-year-old “Topshopper”.

WITH clothes hanging from the wall, and used paper cups on the table, Shepherdson’s office feels like an unloved meeting room rather than the office of one of the most powerful women in retail. Drapers Record, the fashion-industry bible, ranks her as the seventh most powerful figure on the high street — and the highest placed woman — behind, among others, Green and Stuart Rose, chief executive of M&S.

But the only clue to her success is the dozens of industry awards that are scattered rather randomly around the room.

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