 Davidson retired from the navy in 1954, in which year he succeeded his uncle Duncan as head of the family, inherited Tillychetly and its farmlands, and married Katherine, secretary to the Canadian chargé d'affaires and daughter of William Jamieson, of Ontario, Canada.In his new role as a landed farmer, having taught himself the agricultural business and being elected to the North-east Area Executive of the National Farmers' Union, Davidson was selected to fight Aberdeenshire West for the Liberals.During the 1966 general election campaign one of Davidson's main policy points was the establishment of a development authority for the North East of Scotland (on the lines of the Highlands and Islands Development Board) and he was a strong advocate on behalf of small farmers and of improving communications in remote areas like the Highlands by improving road links to the major cities.