Britain's former prime minister Margaret Thatcher was in hospital Saturday recovering from a minor operation to remove a growth in her bladder and may remain there over Christmas, friends said.
The 87-year-old "Iron Lady", Britain's first and only female premier, was doing "absolutely fine" having been admitted to hospital on Thursday feeling unwell, her spokesman said.
But the operation has raised fresh fears for the health of Britain's conservative prime minister from 1979 to 1990, who has been a subdued figure in recent years and a far cry from the fiery figure of her heyday.
Current Prime Minister David Cameron, who like Thatcher leads the Conservative Party, wished his predecessor "a speedy recovery", his 10 Downing Street office said.
Thatcher -- the 20th century's longest continuous occupant of Downing Street -- has suffered a series of minor strokes and in 2002 was told by doctors to quit public speaking.
With dementia taking hold, she has appeared increasingly rarely in public. Her daughter Carol once revealed that she had to be repeatedly reminded that her husband Denis had died in 2003.
Public relations executive Lord Tim Bell, Thatcher's adviser for her three general election victories, said she had undergone "minimally invasive" surgery.
"She felt unwell earlier in the week. She went to the doctor. The doctor sent her to the hospital," he told BBC television.
"The hospital examined her, discovered a small growth in her bladder and they decided to remove it using what they describe as minimally invasive surgery, so no heavy anaesthetics and so on.
"The operation was a complete success, her condition is satisfactory. She'll stay in hospital for a few more days to recuperate and then she'll go home.
"All operations are difficult, doesn't really matter what age you are. But she's very tough and the doctors are perfectly happy, The surgeons are happy and they say the operation's been completely satisfactory."
Thatcher's daughter has been at her side in hospital. Her son Mark is believed to be outside Britain on holiday.
Asked how long she might remain in hospital, Bell said: "A few days is the phrase being used.
"It's perfectly possible she'll be there across Christmas."
Two years ago Thatcher missed an 85th birthday party at Downing Street laid on for her by Cameron.
In July, she was not well enough to attend a Downing Street lunch thrown by Cameron for Queen Elizabeth II to celebrate the monarch's diamond jubilee.
The other surviving former prime ministers -- Gordon Brown, Tony Blair and John Major -- all attended.
But in October, Thatcher was sufficiently well to mark her 87th birthday with lunch at a restaurant in London with her son and his wife.
Thatcher's health was thrust into the global spotlight this year when US actress Meryl Streep starred in a controversial Hollywood film about her.
"The Iron Lady" drew criticism from Cameron and others for concentrating on ex-premier's dementia. Streep won an Oscar for the role.
Reaction on social media in Britain to news of Thatcher's operation was deeply split, reflecting the divisive legacy of her economic reforms and battle with the country's trade unions in the 1980s.
On the world stage, she built an extremely close "special relationship" with US president Ronald Reagan which helped bring the curtain down on Soviet Communism.