In the 2019 general election, Turmaine was selected as the Labour parliamentary candidate for his home seat of Chesham and Amersham, where he finished third below the Liberal Democrat candidate and the Conservative incumbent Cheryl Gillan.[14] He then held his Holywell seat in the 2022 council election with a reduced majority.[15] In July 2022, Turmaine was again selected as the Labour parliamentary candidate for Watford.[7] Throughout the 2024 election campaign, Turmaine pledged to reduce the tax burden on Watford families and waiting times at Watford General Hospital as well as recruiting more teachers to Watford schools, in line with the Labour Party manifesto.[16] He was elected as the MP for Watford in the 2024 general election, defeating the Conservative incumbent Dean Russell with a majority of 4,723 votes.[1] In his victory speech, Turmaine thanked the people of Watford for putting their trust in him.[17]