 Hawthorne was active on many committees and advisory bodies concerned with energy matters, in particular the Advisory Council on Energy Conservation, of which he was chairman from its inception in 1974.Hawthorne was elected to the fellowship of the Royal Society in 1955, and was knighted in 1970.He became Head of the Department of Engineering in Cambridge in 1968 and was appointed Master of Churchill College, Cambridge in the same year (1968–1983).