With the enemy now in possession of a coastline extending from the North of Norway to Dieppe, his jumping off points are many. In the event of an attack with London as the principal objective, it would appear reasonable to suppose that an attempted landing would be on the east or south-east coast of Britain, unless the situation vis-a-vis Eire had materially changed for the worse. The element of surprise being an important factor, the sea-route selected would probably be in the neighbourhood of the shortest available, The Thames Estuary is another possible means of approach.