Lord Tim Bell, the leading PR and advertising figure who was a close adviser to Baroness Thatcher, said she was expected to need several days of recuperation. It could mean she will spend Christmas in hospital, where she has been accompanied by her daughter Carol.
Lord Bell said the former politician had been in some pain earlier in the week and was sent by her doctor to hospital where it was decided the operation was required.
It was a short procedure using what was described as "minimally invasive surgery", he said."She's fine," he added.
More top news
Charles Bronson - Britain's most notorious prisoner- has sent Alton Towers crash victim Leah Washington a get well picture
Weather: Lunchtime update with Alex Beresford
A 32-year-old Leukaemia patient is undertaking a marathon challenge from his hospital room to try to raise £50,000 for charity.