Surgery to help heal former prime minister Margaret Thatcher's broken arm has been a success but she will remain in hospital for the next few days, her son said yesterday. "The surgeon said it was a complete success. We're all delighted and relieved that it's gone so well," Mark Thatcher told reporters outside the Chelsea and Westminster hospital in London.

Dame Thatcher, 83, Britain's first woman prime minister, was taken to hospital a week ago after breaking her arm in a fall at her London home. The operation yesterday was to insert a pin to help heal the fracture in her upper arm.

"There is no prospect of her leaving over the weekend under any circumstances," Mark Thatcher added, saying his mother would stay in hospital at least until next Wednesday.

Dame Thatcher has had intermittent health scares since she was forced from power by her own Conservative Party in 1990.

She suffered a series of mild strokes in late 2001 and 2002 and cancelled several engagements a few months later due to an undisclosed illness. On the advice of her doctors, she cancelled her public speaking schedule and cut back personal appearances.

Dame Thatcher's daughter Carol revealed in 2008 that her mother had been suffering from dementia for several years and often struggled to remember things - including that her husband Denis had died in 2003.

One of her most recent public engagements was a meeting with Pope Benedict in Rome last month.