Baroness Amos is the third ever woman to become leader of the House of Lords.
Baroness Amos visited African nations in the run-up to war
Already the first black woman to sit in cabinet she was moved to her new role in the wake of the sudden death of Lord Williams of Mostyn.
She takes over at a tough time when rebellions in the upper house are widely predicted over issues such as foundation hospitals and law and order.
Not only that but Tony Blair has pledged to get rid of the remaining hereditaries in the Lords which is likely to make her job challenging from the start.
Lady Amos spent the past few months as international developement secretary - a job she got after the resignation of Clare Short over the Iraq war.
As a foreign office minister Lady Amos had a key role ahead of that conflict.
She canvassed African leaders in the run-up to the war in Iraq, travelling to Cameroon, Angola and Guinea to urge them to support the United States and Britain in the United Nations Security Council.
She is the second black Cabinet minister, following Paul Boateng, who was appointed chief secretary of the Treasury last year.
Baroness Amos was Parliamentary Under-Secretary of State, Foreign and Commonwealth Office since 2001.
Previously she was the Government Whip from 1998 to 2001 and a co-opted member, European Union Sub-committee F (Social Affairs, Education and Home Affairs) from 1997-98.
She was spokesperson for social security 1998-2001, international development since 1998, women's issues 1998-2001, and foreign and commonwealth office 2001.
Born in March 1954 in Guyana, Valerie Ann Amos began her career in local government, working in various London boroughs from 1981 to 1989.
She was educated at Townley Grammar School for Girls before completing a degree in sociology at Warwick University in 1976, a masters degree in cultural studies from Birmingham University in 1977 and doctoral research at University of East Anglia.
She was chief executive of the Equal Opportunities Commission from 1989 to 1994, and then director of Amos Fraser Bernard from 1995 to 1998.
She became a life peer in 1997, taking the title Baroness Amos, of Brondesbury in the London Borough of Brent.
She was deputy chair of the Runnymede Trust, a trustee of Institute of Public Policy Research and involved in Project Hope, an NGO which promotes healthcare.
Her charity works involved being the chair of the board of governors at Royal College of Nursing Institute from 1994 to 1998 and one of the directors of Hampstead Theatre.