 He served as a councillor on Westminster City Council from 1956.Le Marchant contested the London safe seat occupied by the Labour Party's George Strauss since its 1950 creation, Vauxhall, at the 1966 general election.He was elected to the House of Commons as Member of Parliament for High Peak at the 1970 general election, and held the seat until he retired from Parliament at the 1983 general election.