LONDON -- Margaret Thatcher turned 80 yesterday with a rare return to the limelight, for a posh party attended by Queen Elizabeth II and the former prime minister's two successors, all celebrating Britain's ''Iron Lady."
Although she has grown frail after several small strokes, Thatcher looked healthy as she arrived at the party, about 15 minutes late. The delay, an aide saidwas caused by to her taking a congratulatory phone call from President Bush.
Wearing a navy blue coat and dress, a string of pearls and a matching handbag that was her trademark, Thatcher smiled and paused for photographs before slowly making her way into the plush Mandarin Oriental Hotel near London's Hyde Park.
Earlier in the day, her assistant, Gilly Penrose, said Thatcher was feeling good about her birthday.
''Her house is looking like a florist's and she's very much enjoying it," Penrose said. Heading the guest list were the queen, and her husband, Prince Philip; Prime Minister Tony Blair; and Sir John Major, Thatcher's immediate successor at 10 Downing St, the prime minister's residence.
Thatcher has become more reclusive in recent years and given up most public speaking on her doctors' advice, but she remains a powerful force 15 years after leaving office as Britain's first female prime minister.
Her free-market philosophy, push to privatize state industries, and hard-nosed battles with labor unions remade Britain's economic landscape.
Even Blair, whose Labor Party languished in opposition while the Conservative Thatcher held power for more than a decade, has adopted many of her views.
''What Churchill did in wartime, Margaret Thatcher did in peacetime," the outgoing Tory leader, Michael Howard, said in a birthday tribute.
''Her political will and her iron courage saw off the threats to our way of life that Britain faced in 1979. We all owe her an enormous debt."
Among the more than 600 guests invited to the party were many members of Thatcher's Cabinets and two current candidates for the Conservative Party leadership, David Davis and Liam Fox, Penrose said.
The other Tory contenders, David Cameron and Kenneth Clarke, were not asked to go.
The queen shook Thatcher's hand on arrival.
Another guest, actress Joan Collins, said she adored Thatcher.
''She is the Iron Lady, and I want to be just like that when I grow up," said Collins, who is now 72 years old.
Caspar W. Weinberger, the late President Ronald Reagan's defense secretary, was the most prominent American to have been invited.
Thatcher's twin children, Sir Mark and Carol Thatcher, were also present. Mark Thatcher pleaded guilty in South Africa last year to unwittingly helping to bankroll a failed coup in Equatorial Guinea.
Also invited were the composer Andrew Lloyd-Webber, the writer Frederick Forsyth, and the novelist and Tory peer Jeffrey Archer, who spent two years in prison for perjury and obstructing justice.
Missing was the former Soviet leader, Mikhail S. Gorbachev, of whom Thatcher once commented ''we can do business together." Gorbachev is scheduled to see her at a London visit next week.