ABSTRACT
The first proposals for a cross-channel link made in the early 19th century were too far ahead of the engineering techniques and geological knowledge of the time to be considered seriously. Many schemes were highly imaginative combinations of bored tunnels, immersed tubes, bridges and artificial islands; one proposal even involved the boring of a short direct route between Folkestone and Cap Gris Nez in Jurassic rocks of mixed lithologies, not ideally suited for tunnelling. Success on tunnelling beneath the Channel depended on gaining a sound knowledge of seabed topography and geology and, in particular, finding the most appropriate rock strata in which to build a tunnel.
