 Aided by his wife's fortune, in 1880 Flower entered Parliament for Brecon, a seat he held until 1885 when the constituency was abolished, and then represented Luton until 1892.He served briefly as a Junior Lord of the Treasury from February to July 1886 in the third Liberal administration of William Ewart Gladstone.He was widely referred to as "the most handsome man in the House of Commons", and was a great favourite of Gladstone who, in 1892, raised him to the peerage as Baron Battersea of Battersea in the County of London and of Overstrand in the County of Norfolk.