In 1784 he was elected to the
House of Commons for
West Looe, a seat he held only briefly. He returned to the Commons as a member for
Saltash between 1787 and 1790. and was duly elected for Truro that year, holding the seat until his death in 1814. On 17 January 1804 Lemon was appointed as one of the
Lords Commissioners of the Admiralty, serving for only a month. According to convention, this meant he had to give up his Parliamentary seat on appointment to the Crown Office and seek re-election to his seat at a by-election in February, at which he was re-elected. ==Amateur musician and composer==