Britain broke off from Europe 450,000 years ago – and it made us the people we are today

The defining features of our island shaped our history in ways we might not even understand

A cross channel ferry is viewed Cap Blanc-Nez as it heads towards the White Cliffs of Dover on January 08, 2019 in Calais, France (Christopher Furlong/Getty Images)

There is much concern, rightly so, at the moment about what humanity is doing to our planet. Our population and environmental impact – from the effects of mining to industrial farming and and greenhouse gas emissions – has grown greatly over the past century. Our species, Homo sapiens, has now replaced natural processes as the dominant environmental force on the Earth, and many scientists are calling for a new geological era to be declared: the Anthropocene, the "recent age of humanity".

This has only recently become the case, however, and the human story has been directed and shaped by the features of the planet that we live on. Our very evolution as an exceptionally intelligent and adaptable species was driven by the active plate tectonics in East Africa over the past five million years. The entire history of civilisation, from the very dawn of agriculture and emergence of the first cities to the founding of the modern states and their interactions with each other, has also been strongly influenced by different facets of the Earth. The underlying signature of the lay of the landscape, availability of different resources, or pattern of winds is discernible in all that we do. It is the Earth that made us.

There are many of these deep links from the grand-scale course of history, and thus the shape of the modern world we all live in, to fundamental features of planet Earth and its own long past. These range from the seemingly trivial – such as why to most of us eat cereal or toast for breakfast – to the deeply profound.

How did climate refugees spur the emergence of civilisation in ancient Egypt? How did Holland's drowned landscape create the modern financial system? How did Earth's recycling system break down over 300 million years ago to accumulate the coal that powered the Industrial Revolution? Planetary forces are just as relevant today and they still underly current affairs and politics. The imprint of the underlying geology can be seen clearly in voting maps of the UK or US, for example.

The Earth has made us in a multitude of different ways, as explored in my new book Origins. but I want to focus here on how one particular feature of Britain has exerted its influence throughout our history.

Perhaps the clearest defining feature of Britain is that we are an island. Britain has a natural defensive moat surrounding it, which, although not impenetrable, does make an amphibious assault much harder than simply marching an army over. The last full-scale invasion, the Norman Conquest of 1066, occurred almost a thousand years ago. Britain has been close enough to trade with continental Europe – and remain intimately involved in the power plays and political manoeuvring when it was in its interest – but is shielded at the same time.

Without this saltwater moat, for example, would the Spanish have been able to invade in the late sixteenth century without an Armada? Or Napoleon’s Grande Armée in the early ninenteenth? Or would we too have rapidly fallen to Hitler's blitzkrieg sweep across Europe, and not survived as a bastion of resistance against the Nazis? This physical separation has thus not only been an advantage for our own sovereignty across history, but a strong island nation has also helped maintain a power balance in the continent as a whole by preventing any one power consolidating a European empire.

Our islandness has had other ramifications for history as well. With clearly defined natural boundaries, and a relatively small extent, England achieved the early unification of feudal fiefdoms into a national identity. And it could be argued that it was this reduced threat of invasion and sense of security from external threats that allowed the progressive dispersion of power away from the autocratic monarch to a more balanced democratic system, beginning with Magna Carta in 1215 and leading to the parliamentary system in place today.

The writer Robert Winder has also argued that by being a relatively small island, Britain was able to exterminate its wolves early in the medieval period and so rid itself of the major threat against keeping large flocks of sheep. While floods of wolves could keep re-emerging from the deep, dark forests across continental Europe, and so resist any attempts at control, Britain could become one huge sheep farm. The wool trade, and in particular selling these fine fibres overseas, generated a great deal of wealth and helped set Britain on track for the industrial revolution.

So this combination of proximity to continental Europe, whilst being physically separated, has been a defining feature of our history. But Britain has not always been an island. Half a million years ago we were still part of continental Europe, physically connected to France by a land-bridge between Dover and Calais.

This land-bridge was eroded away by a sudden, catastrophic event. Some 450,000 years ago, during not the last ice age but the one five glacial cycles earlier), a vast lake of meltwater became trapped between the Scottish and Scandinavian ice sheets. This eventually spilled over the landbridge, forming colossal waterfalls, before the entire damn gave way and the eastern end of the English Channel was rapidly carved open by this megaflood. The white cliffs of Dover are all that remains as stumps of this past connection between Britain and the continent.

British history would have played out very differently if this landbridge physically connecting us to the continent had remained. And this is just one example of the enduring effects features of the planet we live on have had on the human story.

Lewis Dartnell is a professor at the University of Westminster. His new book Origins: How the Earth Made Us is published by The Bodley Head (£20).