The former Northern Ireland Secretary, Mo Mowlam, is reported to be critically ill.
The former MP, who is 55, is in London's King's College Hospital, where a spokeswoman has described her condition as critical but stable.
Ms Mowlam previously suffered a brain tumour, and her increasingly frail appearance in recent months has prompted fresh fears for her health.
One of Labour's most popular figures, she stood down from the House of Commons at the 2001 election after 14 years as an MP.
She was made Northern Ireland Secretary when Labour came to power in 1997 and won universal admiration for her perseverance in working towards the Good Friday peace agreement the following year.
It was magnified by the fact that she was recovering from treatment for the brain tumour at the time.
But her honesty on everything from the Royal Family to her experimentation with cannabis upset party managers, and after persistent rumours that senior party figures were offering the media negative comments about her role after she left the Northern Ireland office, she decided to stand down from party politics.
She became even more outspoken after that, saying it was harder and harder to defend what the Labour government was doing.
