Suits join arty animals for Tate's big bash

The new Tate Modern gallery at Bankside will open with an unprecedented series of lavish parties for the powerful, the famous, and - most importantly - the rich.

According to the strict hierarchy of its secret guest lists, the coolest cat in the land is not a rebel who cuts cows in half but the man from Unilever.

Those who care about such things will see this mini-season as the acid test of who is in and out of fashion in Blair's Britain. But the real message is that even in the wacky, iconoclastic world of BritArt, old-fashioned cash is what really counts.

The Tate has been besieged with requests for tickets to its biggest event, a gala in the huge central space of the former power station on the South Bank, on 11 May, to be broadcast live by the BBC. Those who dance with Madonna, get pickled with Damien Hirst, or do small talk with Yoko Ono will no doubt feel themselves to be at the event of the year, with a mere 4,000 of the best people.

Others will wonder why they weren't at the civic reception that morning to see the Queen open the new gallery to the sound of a fanfare by Sir Harrison Birtwistle. And even some of the few deemed important enough to have stood by the river with Her Majesty will suffer nagging self-doubt at not having been asked to the most exclusive event of all. That will begin at 7pm on 3 May, when 250 people will meet for a private view followed by a champagne dinner in the Turbine Hall. These will be the most important guests of the lot. The invitation calls this group the Benefactors.

"They tend to be very private," said Erica Bolton, who is in charge of public relations for the launch of Tate Modern. "I wouldn't want to name them."

They definitely do not include Ivan Massow, chairman of the Institute of Contemporary Arts, whose surprising lack of an invitation has been trumpeted in diary columns.

The least secret Benefactors are bodies such as the Millennium Commission, the Arts Council, and Southwark council. Their representatives will dine alongside corporate sponsors such as Donald Fisher, the chairman of Gap, Garfield Weston of Fortnum & Mason, and Alfred Taubman of Sotheby's.

Individuals whose charitable trusts support the Tate include the publisher Baron Paul Hamlyn, the textile magnate Sir Harry Djangoly, and the art collector Janet Wolfson de Botton, who has donated a considerable number of works to the new gallery. The Benefactors also include a sprinkling of star names, including Neil Tennant of the Pet Shop Boys, who gave the Tate £10,000 the group won in a libel trial.

However, only one Benefactor gets a party all to himself: Niall Fitzgerald, the 54-year-old head of Unilever, will host a dinner on 4 May to celebrate his company's commissioning of new work from one artist a year for the next five years, at £1.25m a time.

The following night the Prudential will give a party in the building, co-hosted by its chief executive, Jonathan Bloomer, and chairman, Sir Roger Hurn. The Millennium Bridge linking the Tate Modern to Blackfriars will be lit up for the first time on 8 May, and, the next day, will be dedicated by the Queen, in her first Bankside photo-opportunity of the week. The old Tate building in Millbank, now relaunched as Tate Britain, will hold its own reception for international guests on 10 May.

Ten years ago an exhibition of modern art would have been unlikely to attract a crowd, let alone a corporate sponsor. Banks and other institutions preferred to be identified with art their clients and directors liked. Impressionists were top of the list, piles of bricks on the floor of the Tate were right at the bottom.

That began to change as the Nineties wore on, but the key moment was the Sensation exhibition at the Royal Academy in 1997 when ordinary people queued to be outraged. A portrait of murderer Myra Hindley made up of handprints of children might not have been to traditional boardroom tastes, but the marketing men could see what sold tickets.

Since then, young British artists have moved to the mainstream and into the arms of the wealthy. Damien Hirst was the first to become a household name, backed by such as Olympia & York and the London Docklands Development Corporation. Modern art events are trendier than Ascot, less vulgar than football at Wembley, and far easier to get people into than Wimbledon.

David Orr, a spokesman for BT, said: "It gives us opportunities to invite people to social events. BT would never want to involve themselves in the Tate's artistic content. It wouldn't be our place to do so."

If soiled, unmade beds and paintings bedecked with elephant dung are sexy, it seems BT wants to be associated with them. "We like to think that we get good value out of this sponsorship because of the prestige, the quality of the art and the access that we are given to it as a result."

BT will pay for the last Tate Modern party on 11 May to which every living artist on display in the gallery has been invited, including the Turner Prize winners Hirst, Rachel Whiteread and Gillian Wearing. Charles Saatchi, Britain's most important collector of young artists, is on the list, although he has yet to reach agreement with the Tate about lending it several major works.

Sir Paul McCartney is expected to attend with his fashion-designer daughter Stella, and Mick Jagger is likely to be there with his former wife Jerry Hall, as they have collected art together over the years. Others from the pop world include Bryan Ferry, who is a patron of the Tate, Brian Eno, and Madonna, who turned up to the opening party for Tate Britain in Pimlico and spent the evening inspecting the art rather than partying. Jack Dee will present some of the BBC's coverage of the party.

Outside, there will be a light show. Inside, Ballet Frankfurt will perform a new piece by William Forsythe about Scott of the Antarctic, and a brass band will play versions of acid-house dance anthems.