It has for some years now almost been folklore that the marine traffic situation in the Dover Strait is one of great potential danger. Very considerable efforts have been made to alleviate the situation. There is a complete traffic separation scheme (the first in the world), there is continuous radar surveillance both from England and France, there are routine broadcasts on v.h.f. to warn mariners of any navigational problems, and there is now a system whereby certain ships report-in. Concurrently with all this activity, the accident rate has dropped significantly over the last decade, especially in fog, and it is a reasonable inference that the reduction in the number and severity of accidents is attributable to this activity.

But patterns of navigation change, and it is necessary for marine administrators to be aware of problem areas as or before they arise so that marine management measures can be introduced when appropriate. Factors to be taken into account are the volume and characteristics of the traffic, the difficulty of navigation and the accident record. One of us has drawn attention to the traffic situation off East Anglia and suggested that a prima facie case for some remedial measures had been made. This paper examines the available evidence in more detail.

First, an account is given of the accident record in the area under consideration (Figs 1, 2) over the last 10 years. Both the numbers and severity of collisions and strandings are discussed.