Neil Stevens

“FOG in Channel; Continent Cut Off”. This apocryphal newspaper headline supposedly illustrates the insularity of the British. Weather-wise, nothing could be further from the truth today, as I peer from a gun emplacement atop the White Cliffs of Dover. The view is stunning. Dead ahead is the bulbous headland of Cap Gris-Nez, the closest tip of France. A few degrees to the left, a sharp eye can make out the distinctive silhouette of Calais Town Hall.

Britain is undoubtedly an island, just not by very much. Not even 21 miles separate England from France here at their closest approach – 33 kilometres measured in suspect units from across the sea. The concrete structure I’ve wormed my way into dates from the last time that distance seemed perilously short, when German forces massed on the French coast during the second world war.

The English Channel carries huge historical and psychological clout. Yet as little as 10,000 years ago, you could have walked across a dry valley in front of me and been in Calais by teatime having hardly got your feet wet.

The full story of how that changed is eye-popping – and we have only recently begun to unearth it. As the political shenanigans surrounding the UK’s decision to leave the European Union continue, this is the story of Britain’s original exit from Europe – a Brexit drama in three acts.

Act 1, Dover

About 450,000 years ago. A ribbon of land stretches into the distance. To the right, a drop plunges perhaps 150 or 200 metres to a plain below. To the left, lapping almost to our toes, are …