From 1954 to 1959, he had a regular role as an Australian lodger in the BBC radio comedy series Hancock's Half Hour. The series, with Comedian Tony Hancock as the eponymous lead and also featuring Sid James, ran for six series. Initially sharper than Hancock's characterisation, Kerr's portrayal eventually developed into a more dim-witted character who became the butt of Hancock's jokes. Unlike James, Kerr did not feature in the television version of the Hancock series. Kerr also starred in the highly entertaining Sunday afternoon radio drama series "The Flying Doctor" in the 1950s, regularly flying in and out of the fictitious Wollamoloo base as he and his "doctor" colleague brought reprobates to justice in the outback. Later, after Hancock had ended his professional partnership with Sid James, Kerr briefly resumed working with him in the first series of the television comedy Citizen James (1960). Kerr's other television appearances in Britain include a Doctor Who serial called The Enemy of the World (1968), with Patrick Troughton, and a long-running part in the early 1960s BBC-TV soap, Compact.