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
Lance Corporal Norman Jackson VC has been given his rightful place on the Great Central Railway War Memorial.
A mentoring scheme to help hundreds of women into leadership roles has been launched by the Labour Party in memory of Jo Cox.
The annual service remembers the 250 airmen who lost their lives in the 1944 Warsaw Uprising