Margaret Thatcher recovering from operation 21 December 2012 Last updated at 20:50 Former prime minister Margaret Thatcher is recovering in hospital after having a growth removed from her bladder. She is understood to have undergone a minor operation to remove the growth. The former prime minister's spokeswoman said Baroness Thatcher is doing "absolutely fine." The 87-year-old, who has suffered from ill health in recent years, was admitted to hospital on Thursday and is expected to be kept in hospital overnight. Friends of the former Conservative prime minister told the BBC they expect her to remain in hospital for a number of days. Very tough Lord Bell told BBC News she had undergone "minimally invasive" surgery. The operation was a complete success and her condition is satisfactory. She'll stay in hospital for a few more days and then she'll go home," he said. She's very tough. The doctors are perfectly happy. They say the operation has been completely satisfactory. Baroness Thatcher was the UK's first female prime minister and served three terms in that post, between 1979 and 1990. She had a series of minor strokes in 2002 and was advised by doctors to stop making public speeches.