Baroness Thatcher was today still in hospital after being taken ill with flu a week ago.
Aides said the former prime minister was expected to remain in the private Cromwell Hospital until at least the start of next week.
She was admitted for tests on Tuesday after failing to recover from flu which forced her to miss a reception at 10 Downing Street to mark her 85th birthday.
A spokesman last night said he had no update on her condition, but added: "We expect her to be staying in hospital into next week."
Newspaper mogul Rupert Murdoch, chairman and chief executive of News Corporation, will this evening deliver a rare public lecture in Lady Thatcher's honour in London.
Mr Murdoch will give the inaugural Margaret Thatcher Lecture, hosted by the right-of-centre Centre for Policy Studies thinktank, which was founded by the former prime minister and her mentor Keith Joseph.
His address, entitled Free Markets and Free Minds, is expected to praise Lady Thatcher's contribution to Britain's economy and society
Lady Thatcher's son Mark visited his mother yesterday and said she was "in good order" and had been talking about the Government's Comprehensive Spending Review.
Last Thursday, Lady Thatcher was forced to withdraw from the reception hosted by Prime Minister David Cameron because of flu.
Friends said she was still being troubled by the illness five days later, and aides called in a doctor to assess her condition.
She was taken from her home to the hospital in west London on Tuesday afternoon.
The one-time "Iron Lady" very rarely speaks in public now on medical advice. However, she does still attend a number of high-profile functions.
Her long-term memory is apparently still good, but she can have trouble remembering things day to day.
In March 2008 the peer, who has previously suffered minor strokes, was taken ill during a dinner in Westminster and spent the night in hospital as a precaution. She was given a clean bill of health by doctors after routine tests.