[1] He worked on the railways, joining the Transport Salaried Staffs Association, but joined the Royal Air Force on the outbreak of the Second World War; after demobilization he returned to his old job.
He served on the National Executive Committee of his Union from 1954 to 1960, and was elected to Wembley Borough Council from 1953 to 1956 and 1957 to 1960.
Howarth served as a magistrate in both the adult and juvenile courts.
In Parliament he was interested in transport, local government and Home Office matters.
He was re-elected in the 1966 election with his majority increased to 2,233, but died in post at his home in Rickmansworth on 8 August 1969, aged 53.