The undulating glass roof of the 1.7-billion-pound (2.1-billion-euro, 2.6-billion-dollar) Westfield London rises out of the redeveloped west of the capital, covering an area the size of Buckingham Palace and its gardens.

Two days before the grand opening, hundreds of workers in day-glo jackets were still frantically putting the finishing touches to the inside and outside of the building, which will contain 265 high-street and luxury shops.

Britain's economy contracted in the last quarter and experts have warned it is heading for recession, but the Australian-owned Westfield - the world leader in shopping centres - is confident the complex will be a success.

"We've opened malls in boom and in recession, or everything in between, and obviously it's a long-term project that is not built for exactly today," Michael Gutman, managing director for Europe and Britain, told AFP.

"We plan to be in this industry for a long time," he added.

Westfield hopes to attract 20 million visitors in the first year, based on its first complex here, in Derby, central England, which got 25 million people through the door in its first 12 months.

"The opening couldn't be at a worse time. It's unfortunate in the short-term, but it was planned a long time ago," said Neil Mason, senior retail analyst for Mintel.

Construction began on Westfield five years ago.

Mason said the promotion of the site in the run-up to Christmas would be "instrumental" in its success. The Evening Standard daily said Westfield is spending a record six million pounds on PR, but this could not be confirmed.

The new complex, spanning 1.6 million square metres, is a temple to shopping but also boasts about 50 restaurants and a cinema. It hopes its offer of central hub of leisure activities will help it weather the downturn.

Westfield is spending money on attracting the more discerning - and wealthy - shoppers, with a section of the centre dedicated to luxury brands such as Tiffany's and Louis Vuitton and 70 concierge and valet staff.

It has also invested 170 million pounds in public transport, upgrading two local subway stations, as well as access roads and social housing.

But if the complex succeeds, it could be at the expense of London's other commercial hubs including Oxford Street in the city centre, the largest retail corridor in Europe, or west London's Kensington High Street.

And it will not be Westfield's last British venture - the group intends to open another retail complex in Bristol, in the west of England, in 2010, and another near the site of the Olympic Games in Stratford, east London, for 2012.