Britain's post-Christmas sales kicked off on Wednesday with retailers hoping a surge in shoppers would make up for a lacklustre run-in to crucial festive trading.

Discounts of up to 70 percent lured thousands of people to London's Oxford Street, the busiest shopping thoroughfare, where at least 900 shoppers queued, some from 4 a.m., to be among the first into Selfridges & Co department store sale.

Beneath yellow banners proclaiming "Buy me I'll change your life" and "I shop therefore I am," hundreds of shoppers mobbed designer concessions Miu Miu, Chloe, Prada and Gucci leaving behind a trail of picked bare shelves.

At Brent Cross, one of Britain's largest shopping malls on the outskirts of London, more than 10,000 shoppers came through the doors in the first hour of trading, spokeswoman Paula Figgitt said. Some 100,000 people were expected by the end of the day.

But with some British retailers having slashed prices unusually ahead of Christmas amid signs consumers were nervous about the credit crunch and reluctant to spend, analysts cautioned a post-holiday spree may be too little, too late to shore up weakened trading and crimped gross margins.

"The first two or three days after Christmas are very important," said Martin Davies, an analyst with data tracker Experian, compiler of the Retail FootFall Index.

"But already in the days before Christmas, the surge of shoppers on to the High Street looked like sales shopping and not pre-Christmas buying."

MODEST GROWTH

How retailers fared over Christmas will not be confirmed until mid-January trading updates, but a British Retail Consortium spokesman said last week it was predicting modest 3 percent like-for-like sales growth during the period.

Thursday is expected to be the biggest shopping day in 2007 with the rest of Britain's major retail brands, including Marks & Spencer, the largest clothing retailer, slashing millions of pounds off retail prices in an effort to get shoppers to spend, according to retail data trackers SPSL.

Industry analysts forecast supermarkets such as Tesco, online sellers and some department stores like John Lewis Partnership will be the winners in the crucial Christmas shopping season when stores can earn half of their yearly sales.

John Lewis on Wednesday reported a record 6.1 percent rise Christmas sales at its department stores compared with a year ago, boosted by demand for iPods, eframes and beauty products.

Managing Director Andy Street said in a statement he expected its post-Christmas clearance sales starting on Thursday this year "to be similarly encouraging."

Still, shares in some High Street clothing retailers, like Debenhams and Next, have sustained deep losses in recent days on expectations consumers could spend less on discretionary items, with shopper morale falling in the face of the impact of higher interest rates and weaker housing markets.

Sarah Smith, 40, a local government employee queuing outside Selfridges from 5.15 a.m. (0515 GMT) on Wednesday, said she had already hit the shops in the days before Christmas to take advantage of early discounting.

Higher mortgage repayments and more expensive electricity bills were changing her spending habits, Smith said. She was budgeting more carefully and targetting what she wanted to buy. On Wednesday, she was on the hunt for a Gucci handbag, her second. "I couldn't buy them at full price now," Smith said.