Margaret Thatcher "doing well" following operation FORMER prime minister Margaret Thatcher has left hospital after having a growth removed from her bladder. The ex-Conservative leader is said to be "doing well" after a minor operation to remove the growth. The 87-year-old, who has suffered from ill health in recent years, was admitted last week and is thought to have left hospital on Friday.Baroness Thatcher is understood to be "convalescing privately" after the operation before Christmas. The delay in her being discharged is believed to have been due to her taking time to recover from the anaesthetic. Shortly after she was admitted to hospital, Lord Bell - a friend and former adviser - told BBC News she had undergone "minimally invasive" surgery. They say the operation has been completely satisfactory," he said. Prime Minister David Cameron sent a message to Lady Thatcher via Twitter after her admission, saying he wished her a "speedy recovery." Baroness Thatcher was the UK's first female prime minister and served three terms between 1979 and 1990. She had a series of minor strokes in 2002 and was advised by doctors to stop making public speeches. Her daughter, Carol Thatcher, has previously spoken of her mother's struggle with dementia. Baroness Thatcher was not well enough to join the Queen for a lunch with the Prime Minister and former prime ministers as part of the Diamond Jubilee celebrations earlier this year. However, in October she was sufficiently well to mark her 87th birthday with lunch at Green's Restaurant and Oyster Bar in London's exclusive St James's district with her son Mark and his wife. Thatcher was thrust into the spotlight last week when confidential documents released under the 30-year rule revealed her shock at the invasion of the Falkland Islands in 1982.