Question: What party was the person who broke Barbara Anne Castle's record as the longest-serving female MP in the House of Commons?

Context paragraphs:
Gwyneth Dunwoody: Gwyneth Patricia Dunwoody (née Phillips; 12 December 1930 – 17 April 2008) was a British moderate Labour Party politician, who was the Member of Parliament (MP) for Exeter from 1966 to 1970, and then for Crewe (later Crewe and Nantwich) from 1974 to her death in 2008.  She had a reputation as a fiercely independent parliamentarian, described as "intelligent, obstinate, opinionated and hard-working".

Michelle Roberts: Michelle Hopkins Roberts (née Thomas; born 29 February 1960) is an Australian politician who has been a Labor Party member of the Legislative Assembly of Western Australia since 1994.  She served as a minister in the governments of Geoff Gallop and Alan Carpenter between 2001 and 2008.  In November 2015, Roberts became the longest-serving female parliamentarian in Western Australia's history, breaking the record set by Liz Constable.  She was a high schoolteacher,

Pat Atkinson: Patricia "Pat" Atkinson (born September 27, 1952) is a Canadian provincial politician.  She was a Saskatchewan New Democratic Party member of the Legislative Assembly of Saskatchewan from 1986 to 2011, and is currently the longest-serving female MLA in Saskatchewan's history.

Santosh Ahlawat: Santosh Ahlawat (born 1965) is an Indian politician and current member of Lok Sabha in 2014 from Jhunjhunu and former member of Rajasthan Legislative Assembly elected in 2013 from Surajgarh as a candidate of Bharatiya Janata Party.  Born in 1965 in Surajgarh, she completed her Masters in Political Science and Economics from University of Rajasthan and worked in the education field.  Later she joined politics.  On 16 May 2014 she became a member of Parliament, and was the first-ever female MP from Jhunjhunu, after a record victory of more than 2.34 lac votes.

Eileen Derbyshire: Eileen Derbyshire, (born 6 October 1930) is a retired English actress, best known for her role as Emily Bishop in the soap opera "Coronation Street".  She has played the character for 55 years as she joined permanently in 1961, making her the longest-serving female cast member in a British soap opera.  She is the mother of sports journalist Oliver Holt.  She was awarded an MBE in the 2010 Queens Birthday Honours list with her fellow co-star and friend, Barbara Knox.

Alice Lau Kiong Yieng: Alice Lau Kiong Yieng () is a Malaysian politician of Chinese origin.  A native of Sibu, she first contested for a seat in the Sarawak State Assembly in the 2011 state election, but was defeated by incumbent Wong Soon Koh.  In the 2013 general election, she was nominated by the DAP for Lanang in Sibu.  She defeated five-term incumbent Tiong Thai King in the general election with a majority of 8,630 votes, or 19.2% of the votes, becoming the first female MP elected from Sarawak from an opposition party.  A pharmacist by profession, she received her MPharm from University of Strathclyde.  Her father, Lau Cheng Kiong, was the chairman of Pelawan branch of Sarawak Progressive Democratic Party (SPDP), a component of the Barisan Nasional government coalition.

Barbara Castle: Barbara Anne Castle, Baroness Castle of Blackburn, PC, GCOT (née Betts, 6 October 1910 – 3 May 2002) was a British Labour Party politician who was the Member of Parliament for Blackburn from 1945 to 1979, making her the longest-serving female MP in the history of the House of Commons, until that record was broken in 2007 by Gwyneth Dunwoody.  She later became the Member of the European Parliament for Greater Manchester from 1979 to 1989.  One of the most significant Labour Party politicians of the 20th century, she served in the Cabinet under Prime Minister Harold Wilson in a number of roles, including as Secretary of State for Employment, Secretary of State for Health and Social Services, and First Secretary of State.

Eugenia Charles: Dame Mary Eugenia Charles, DBE (15 May 1919 – 6 September 2005) was a Dominican politician who was Prime Minister of Dominica from 21 July 1980 until 14 June 1995.  She was Dominica's first, and to date only, female prime minister, as well as the nation's longest-serving prime minister.  She was the second female prime minister in the Caribbean after Lucina da Costa of the Netherlands Antilles, and the first woman elected in her own right as head of government in the Americas.  She was the world's third longest-serving female Prime Minister, behind Indira Gandhi of India and Sirimavo Bandaranaike of Sri Lanka, and the world's longest continuously serving female Prime Minister ever.  Charles was also Dominica's first female lawyer.

Ruth George: Ruth Stephanie Nicole George (born 27 November 1969) is an English Labour Party politician, who became the Member of Parliament (MP) for High Peak in Derbyshire at the 2017 United Kingdom general election.  She defeated the incumbent Conservative MP Andrew Bingham with a swing of 7%.  In doing so, she became the constituency's first female MP.

Hedy Fry: Hedy Madeleine Fry, PC, MP (born August 6, 1941) is a Trinidadian-Canadian politician and physician.  She is the longest-serving female Member of Parliament since winning eight consecutive elections and represents the constituency of Vancouver Centre since the 1993 election, when she defeated incumbent prime minister Kim Campbell.

Supporting paragraphs: Barbara Castle Gwyneth Dunwoody
Answer: Labour Party