Buck was selected to stand for election for Labour through an
all-women shortlist, in a seat which was based largely on the former Westminster North constituency, held narrowly at the
1992 general election by the former
Conservative minister
John Wheeler. He retired, and Buck was elected at the
1997 general election as the Labour MP for
Regent's Park and Kensington North with a majority of 14,657 (31%), on a night which saw a historic Labour
landslide win. She made her
maiden speech on 17 June 1997, and would serve continuously as an MP for 27 years, in constituencies which included the ward she represented as a councillor. In a 2005 profile, Buck was described as "A bright and humorous centre-left feminist" who "has the perfect
New Labour pedigree." However, she did become a member of
Prime Minister Tony Blair's government in the wake of the
2005 general election, as the
Parliamentary Under Secretary of State at the
Department for Transport. Buck sat on the
Home Affairs Select Committee from 2006 to 2010. Following Labour's election defeat, Buck nominated
Ed Miliband to succeed
Gordon Brown, who had replaced Blair as Labour leader and prime minister. Miliband subsequently won the party's
2010 leadership contest. During his tenure as
Labour leader, Buck served as Shadow Minister for Welfare Reform from 2010 to 2011 and Further Education from 2011 to 2013. She was appointed
Parliamentary Private Secretary to Miliband, alongside
Wayne David, in 2013, and continued in the position until 2015. Cooper came third, with
Jeremy Corbyn becoming party leader; Buck did not serve in any posts during his leadership tenure. In July 2015, she was appointed to the Work and Pensions Committee, remaining on it until 2017. From 2015 to 2017, she was also a member of the
Joint Committee on Human Rights and the
Panel of Chairs. At the
2017 general election, Buck increased her majority by 14.7%, to 11,512 (26.6%), representing a 10.8% swing to Labour in the constituency. Buck campaigned for 'Remain' in the
2016 European Union membership referendum, and voted against the
triggering of Article 50 in Parliament. In a message posted on her website in November 2018, she wrote, "Most of my constituents know that I have always believed that
Brexit would be a disaster and that no possible deal could replicate the advantages of our remaining in
the EU." She continued, "And while I respect the deeply held views of many people who voted to leave, the fact remains that the 'Leave' campaign was based on a raft of promises which could never realistically be delivered, and a false prospectus was put before the British people." In December 2018, Buck's
Private Member's Bill received
Royal Assent as the Homes (Fitness for Human Habitation) Act, coming into force on 20 March 2019. If a landlord failed to let and maintain a property that was fit for human habitation, the Bill would give tenants the right to take action in the courts. The Bill received cross-party support. She was re-elected at the
2019 general election, with a small swing away from Labour, again with a substantial majority of 10,759 (25.07%), suggesting that Westminster North had become a safe seat. Nationally, Labour were defeated for the fourth time in a row, and a
leadership election was held in 2020 to replace Corbyn. Buck nominated
Keir Starmer, who won, and consequently became party leader. She was appointed Shadow Minister for Social Security in July 2020, serving in the role until she stepped down in September 2023. In January 2024, Buck announced that she would be standing down at the
next general election; it was subsequently called in May, and held in July that year. She was appointed a Dame Commander of the
Order of the British Empire in the
2024 Birthday Honours, which were announced in June. ==Political views==