Abstract
This paper provides a critical appraisal of the use by the British Ministry of Transport of a spatial interaction model to assess the viability of the first proposal by the Port of Bristol Authority for the development of a new dock at Portbury. It is argued that the Ministry's use of the model was simplistic, and it is shown that, had more intelligent and imaginative use of the model been made, the model forecasts would have suggested that Portbury was a marginally viable, rather than a hopelessly nonviable, project. Notwithstanding this finding, arguments are produced to suggest that the government decision to reject Portbury in 1966 was sensible, even though it was based on a partially flawed analysis.