Betjeman was for over 20 years a trustee of the Bath Preservation Trust and was vice-president from 1965 to 1971, at a time when Bath—a city rich in Georgian architecture—was coming under increasing pressure from modern developers and a road had been proposed to cut across it. He also created a short television documentary called "Architecture of Bath", in which he voiced his concerns about the way the city's architectural heritage was being mistreated. From 1946 to 1948 he had served as Secretary to the Oxford Preservation Trust. Betjeman was also instrumental in saving the Duke of Cornwall Hotel in Plymouth.