New Labour's fixer: Welcome to Sally's irresistible salon

She charmed Bill Clinton and Kevin Spacey into attending Labour's conference. Some people say Sally Greene has also rescued West End theatre. Sonia Purnell on a socialite and her powerful friends

Even by her own richly oxygenated standards, London's premier political socialite Sally Greene has had a dizzying couple of weeks. First, she took much of the credit for arranging Bill Clinton and Kevin Spacey's triumphant appearance at a star-struck Labour Party conference. Now she has garnered ecstatic reviews for another US import – the veteran actress Elaine Stritch, whose "song and gabfest" show At Liberty opened on Wednesday to great acclaim at Greene's personal powerbase, the Old Vic theatre in Waterloo.

The charming, coquettish theatre impresario is also New Labour's most glittering salon hostess, and occupies the very centre of a dazzling network of influence that stretches across both showbusiness and serious political power.

"Nobody I've ever asked for help has ever said no," she is fond of proclaiming, and few who know her would argue with such a boast from a woman who is certainly never afraid to ask. She gives, too, working an endless succession of party rooms as one of the Blair project's most enthusiastic advocates. Hers is a world in which the right introduction can raise millions of pounds or influence major decisions.

Ms Greene and her husband Robert Bourne, property tycoon and former bidder for the Millennium Dome, give soirées at their antique-filled house in Cheyne Walk, Chelsea, which are attended by an eclectic mixture of famous and powerful people. Ralph Fiennes may be found rubbing shoulders over a glass of champagne with the Downing Street policy wonk Roger Liddle or the aristocratic fixer Sir Evelyn de Rothschild.

With her girlish enthusiasm, penchant for split skirts and thigh-boots, Sally Greene has long been irresistible to influential men. But she is equally popular with women such as Elisabeth Murdoch and Dame Judi Dench, who have been won over by that Clintonesque gift of making everyone feel like her best friend. Not bad for a 47-year-old mother of two, whose mother-in-law thinks she dresses like a tart, and who worries about whether to wear perfumed hand-cream on prison visits.

"Bourne and Greene" target their invitations with the precision of championship darts – and expect something in return. On one occasion, the evening built up to an impassioned plea from the hostess for cash to fund theatre productions. On another the teetotal Ms Greene co-hosted a reception for the New York media queen Tina Brown, who was over to collect her CBE. Ms Brown agreed to give the fashion designers Stella McCartney and Vivienne Westwood some invaluable free publicity in return for their designing the dressing rooms at the Old Vic.

Some believe the recent change in fortunes of the London theatre scene is due, in part, to Ms Greene and her ability to charm people. She has wooed any number of A-list names on to the management boards for the Old Vic and her other theatre the Criterion – from David Suchet to Sir Jeremy Isaacs, and Sir Elton John to Kevin Spacey. She rescued the Old Vic from becoming a lap-dancing club, and then revived its fortunes with the aid of £1.8m raised from her friends.

Ms Greene's rise up the social ladder began when she was an actress, but pregnant and looking for something to do. Her father suggested to Mr Bourne that he buy Richmond Theatre as "she might be rather good at running it". He did, she was, and the rest is history.

Her latter-day social salon has attracted the wrong sort of publicity, however – such as when Peter Mandelson was treated to a birthday party at her home in 1999 at a reported cost of £5,000 for 30 close friends. Mr Mandelson was riding high as Northern Ireland Secretary and known to have influence over the Prime Minister. He was seen, rightly or wrongly, as instrumental in deciding the future of the Dome – for which it turned out Mr Bourne was a leading bidder. The couple were unflatteringly likened to the property tycoon and his party-giving wife Donald and Ivana Trump.

She defended herself by pointing out she was close to Mr Mandelson in her own right, having persuaded him to join the board of the Old Vic, and that the party was in no way connected to her husband's business pursuits. The affair appeared to temper her normally boundless social ambition – but not for long. When Oxford student Chelsea Clinton attracted unwelcome headlines suggesting she was aiming for "a degree in partying", it emerged that some of her outings were of a more cultural nature – with Sally Greene. Chelsea's most attention-grabbing appearance was at a première of the film The Shipping News. And the charity the première raised money for? The Old Vic. It's not what you know but who you know – or, as Sally Greene would doubtless say, you only get what you ask for.