Princess Margaret was last night in the care of specialists at a private London hospital where she was being fed through a tube.

Doctors were carrying out a thorough assessment of the Queen's 70-year-old sister who was admitted to the King Edward VII Hospital on Wednesday suffering from a severe loss of appetite after a suspected second stroke just before Christmas.

Buckingham Palace said Margaret had spent a comfortable night and her condition was continuing to be assessed.

Her children, Viscount Linley and Lady Sarah Chatto, issued a joint statement thanking the Princess's friends and well-wishers for their kind messages.

Lady Sarah arrived at the hospital in a chauffeur-driven Mercedes last night to visit her mother. Lord Linley visited her on Wednesday night.

Margaret was taken to hospital from Sandringham where she had been given special nursing care but failed to respond to treatment.

The Princess was eating so little she had to be admitted to hospital.

There were no immediate plans for the Queen, Queen Mother and Duke of Edinburgh, who have remained at Sandringham, to visit.

It is understood Lord Snowdon, Margaret's ex-husband, was keeping in close touch.

Margaret's illness, described on Wednesday by the Palace as "a cause for concern", was thought to be at a critical stage as doctors attempted to build up her strength.