A megaflood in the English Channel

Abstract

Island Britain is deeply embedded in our psyche. Indeed, the white cliffs of Dover are a modern icon of our national identity, with the perception that the English Channel (La Manche) repeatedly protected us from “unwanted continental influences” throughout history. But when did this concept of Britishness evolve? It is well known that, less than 500 000 years ago, when our hominid ancestors battled with the glacial world, southern Britain was physically connected to northern France via a rock ridge at the Dover Strait. This allowed them, and other land animals, to migrate back-and-forth as the climate cooled and warmed. This land bridge disappeared to form the isolated Britain we know today, but how it did so has been the subject of much debate. Did it just slowly erode away in a series of cliff falls as it was weakened by tides and storms, as we see around the coastline today, or did something more dramatic happen? Once posed, this question remained unanswered for more than 50 years, until in 2003 we took to the water with the latest geophysical equipment and discovered an astonishing landscape below the waves. Over the following years we have slowly pieced together evidence for an array of features carved into the floor of the English Channel that we believe show that the rock ridge was removed by a catastrophic event. This event literally changed the course of our history, with the implications resounding right up to the political climate of today.