 He was elected to the London County Council in 1952, representing Stoke Newington and Hackney North and was a council member of Toynbee Hall and the Fabian Society.Sandelson unsuccessfully attempted to enter Parliament many times before he finally gained election.He contested Ashford in 1950, 1951 and 1955, the Beckenham by-election in 1957 and Rushcliffe in 1959.