Fears were growing last night for the health of Princess Margaret after she was taken to hospital suffering from a "severe loss of appetite".
The Queen's 70-year-old sister had a suspected second stroke just before Christmas.
An initial improvement in the Princess's condition faded as she failed to eat sufficiently to maintain a recovery.
Yesterday afternoon, she was driven by car from Sandringham, the Royal Norfolk estate where she was taken ill more than two weeks ago, to London's King Edward VII Hospital.
Last night, the Princess's son son, Viscount Linley, spent 40 minutes at his mother's bedside. He arrived in a black taxi carrying a large bouquet of flowers.
Meanwhile, the Princess's official engagements were cancelled as her Royal role was put on hold.
Speculation mounted that the latest setback could signal the end of the Princess's public life.
Medical experts agreed that the fun-loving Princess, who lived life to the full, may now be paying the price for years of late-night parties, chain-smoking and heavy drinking.
After Margaret was admitted to hospital, the Palace issued a statement confirming that her health remained a cause for concern.
"On the advice of her doctors, Princess Margaret has been admitted to the King Edward VII Hospital in London this afternoon," the statement said. "One of the consequences of her recent apparent stroke has been a severe loss of appetite.
"There was some hope at the end of last week that the Princess might be responding to treatment and extra nursing care at Sandringham.
"However, this improvement has not been maintained and her condition remains a cause for concern.
"Her doctors have therefore decided, following consultation with the Princess and the Queen, that the Princess should be admitted to hospital where her condition can be more closely monitored."
Last night, the Stroke Association said that severe loss of appetite following a stroke was a common side-effect of the debilitating and sometimes fatal condition.
"A stroke can affect people's ability to swallow and therefore make it more difficult for them to eat," said Margaret Goose, the association's chief executive.
"Loss of appetite can be directly due to the stroke itself or it may be a result of any number of other conditions.
"Strokes can also cause depression and loss of appetite may be due to depression."
Princess Margaret has survived some major health scares over the years. She had part of a lung removed in 1985, she suffered a mild stroke in 1998 and, the following year, badly scalded her feet in the bath, causing lasting injury.
She has also suffered migraines, laryngitis, bronchitis, hepatitis and pneumonia.
The operation on her lung did not stop her smoking, even though four monarchs - Edward VII, George V, Edward VIII and the Princess's own father, George VI - all died of smoking-related illnesses.
Margaret was said to be getting through 30 a day within a few months of surgery.
But she had apparently given up cigarettes by the time of her stroke, 13 years later, when the Princess complained of dizziness, chest pains and a headache while dining with friends on the Caribbean island of Mustique.
It was back on Mustique, in 1999, that Margaret suffered severe injury when she stepped into a scalding hot bath.
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