Throughout his two terms in Parliament, Proudfoot was particularly vocal on matters relating to the retail sector. During his first term (1959 to 1964) he was an early advocate of decimal coinage and opposed the use of trading stamps. He supported capital punishment whenever that was debated. Proudfoot never held ministerial office although he served as Parliamentary Private Secretary to Sir Keith Joseph (minister of housing and local government) between 1961 and 1963. During his second term (1970 to 1974) he was very vocal on the subject of commercial radio while legislation to allow it was being enacted. Fellow MPs gave him the nickname "Radio Proudfoot". The main thrust of his interventions was an attempt to promote the local character of independent radio stations along the lines of the former offshore stations like Radio 270 (see below). In 1970 he engaged as his secretary one Christine Holman, who was later to marry the politician Neil Hamilton and become famous under her married name.