Lynch was given just over six weeks to retain the marginal seat of Halifax for Labour having been selected as the party's candidate only at the end of March 2015. Labour's search for a new candidate was triggered by the decision of sitting MP
Linda Riordan in February to stand down on health grounds. Her decision, and Lynch's subsequent selection, set up one of the most closely fought contests in Yorkshire in the election. Riordan had held Halifax for Labour in 2010 by a majority of just 1,472 votes, and the seat was considered a key target for the
Conservative Party. Lynch was successful on election night and held the Halifax seat for Labour with a majority of only 428 votes over the Conservative candidate. Lynch made her maiden speech in the House of Commons on 9 June 2015. She stated her priorities as being
human rights, the UK's relations with Europe and the protection of services at
Calderdale Royal Hospital. In the
2017 general election, Lynch increased her majority to 5,376 (11.1% of those voting) over the Conservative candidate, Chris Pearson. Lynch was a member of the Environmental Audit Committee from July to October 2015 and was appointed to the Procedure Committee in February 2016. Lynch was appointed as an Opposition Whip in the Commons on 18 September 2015. Lynch is the chair of the All-Party Parliamentary Group on Fairtrade and a Co-Chair of the British Museum group and of the Population, Development and Reproductive Health group. Following the October Shadow Cabinet reshuffle and the firing of
Dame Rosie Winterton as
Chief Whip, Lynch resigned as a whip. She was reappointed to the front bench by Labour leader
Jeremy Corbyn on 3 July 2017, taking on the role of Shadow Flooding & Coastal Communities Minister within the Environment, Food and Rural Affairs team. In 2018, Lynch led the Protect the Protectors campaign to secure harsher sentences for people convicted of assaulting emergency service workers. In the
House of Commons chamber, she spoke about the experience of her parents, both of whom were emergency service workers who had faced violence whilst on the job. She also spoke about her experience shadowing a
police constable from the
West Yorkshire Police when he was involved in an altercation when attempting to make an arrest. In the 2019 general election, Lynch was re-elected to the
Halifax constituency with 21,496 votes out of 46,458 cast, and a majority of 2,569. Lynch endorsed
Keir Starmer in the
2020 Labour Party leadership election, and was appointed as the
Shadow Minister for Immigration following his victory in April 2020. She held this position until the
minor reshuffle in May 2021, when she swapped roles with
Bambos Charalambous to become the Shadow Minister for Crime Reduction and Courts. In the
November 2021 British shadow cabinet reshuffle she was made Shadow Minister for Security. She focused on issues such
Boris Johnson's relationship with
Alexander Lebedev, hostile state threats,
Martyn's Law and the effectiveness of the
Criminal Injuries Compensation Authority (CICA). She also led the Labour Party's scrutiny of the National Security Bill from its introduction to Parliament in May 2022 to it becoming law in July 2023. Lynch announced in May 2024 that she would step down from Parliament at the
forthcoming general election. ==Personal life==