Hilary has served as an opposition frontbench spokesperson on Education (1988–1992). In 1994, she was appointed the Treasury Affairs Team. In 1995, she was made Opposition spokesperson on the Environment and London, with responsibility for Local Government.
After Labour’s 1997 general election victory, she was appointed as Minister of State at the Department of Environment, Transport and the Regions with responsibility for Local Government and Housing.
As Minister for Regions she advanced the Government’s regional policy helping areas such as the North East of England. She also had special responsibility for Social Exclusion and oversaw the creation of the Government’s Social Exclusion Unit.
In 1999, Hilary was made a member of the Privy Council. Following the 2001 General Election, Hilary was promoted to the Cabinet and given the cabinet position of Parliamentary Secretary to the Treasury and Government Chief Whip. She was only the second woman to hold the position. She was re–appointed as Government Chief Whip following the 2005 General Election.
In 2006, Hilary was appointed to the post of Chancellor of the Duchy of Lancaster, Minister for the Cabinet Office and Social Exclusion. In June 2007, Hilary announced her decision to step down from the Government and return to the backbenches after 18 years as a Party spokesperson and Government Minister.