In February 2024, Maguire was named as the Liberal Democrats' prospective parliamentary candidate for the North Cornwall.[2] At the 2024 general election, Maguire was elected to Parliament as MP for North Cornwall, receiving 47.0% of the vote and a majority of 9,957.[3] The incumbent Conservative MP was unseated with a vote swing of 24.9% towards Maguire.[4]
Ben Maguire was sworn in after making the parliamentary oath in Cornish.[5][6][7] On 15 July, Andrew George and Ben Maguire submitted a letter in support of Cornish devolution to the Prime Minister, Keir Starmer. Maguire described existing devolved responsibilities as window-dressing that did not go far enough. He also stated his support for a Cornish Assembly akin to the Welsh Senedd, and rejected the notion of a Mayor of Cornwall.[7][8]
On 18 September 2024, Ed Davey announced his new Frontbench Team, in which Ben Maguire took the position of Shadow Attorney General.[9]
On 10 October 2024, Ben Maguire made his maiden speech in the House of Commons.[10] Maguire has served as a member of the Home Affairs Select Committee since October 2024.[11]
On 16 October 2024, during Prime Minister's Questions, called on Keir Starmer to meet with the six Cornish MPs a Cornish Asembly, and critisied the top-down approach Westminster took towards devolution. Keir Starmer noted he was encoraging "broader" devolution deals regarding Combined Authorities, but agreed to meet with the MPs.[12][13]
