The former Northern Ireland Secretary was taken to King's College Hospital earlier this month after she fell and injured her head.
She has not regained consciousness and, last week, she was transferred to the hospice. Food and water have been withdrawn from her in the past few days in accordance with a living will she had made in which she asked not to be resuscitated.
Ms Mowlam - one of New Labour's most popular figures - stood down from the Commons at the 2001 general election after 14 years as an MP. Tony Blair made her Northern Ireland Secretary when Labour swept to power in 1997 and she quickly made a name for herself as a down-to-earth and brutally honest operator.
She won widespread acclaim for her perseverance in working towards the Good Friday peace agreement the following year. Her achievements were all the more remarkable because she was recovering from for a brain tumour at the time.
Renowned for her light-hearted disregard of formality, kicking off her shoes and chewing gum in meetings, she reputedly took her wig off to break tension in tense talks.
She took a political risk in 1998 by entering the Maze Prison to speak to convicted paramilitaries when it became clear the peace process needed their backing.
Loyalist prisoners had withdrawn their support but after her face-to-face talks with prisoners, the paramilitaries' announced they were rejoining talks.
Ms Mowlam was born in Watford on 18 September, 1949. She is married to Jon Norton, a merchant banker, who already had two children.