John Luther Mercer (born 17 August 1981) is a British politician and former British Army officer who has served as Minister of State for Veterans’ Affairs since October 2022, having previously served from July 2022 to September 2022. He was Parliamentary Under-Secretary of State for Defence People and Veterans from July 2019 to April 2021. Mercer has been Member of Parliament (MP) for Plymouth Moor View since 2015. He is a member of the Conservative Party.