I remember standing in the Boxgrove quarries 15 years ago, marvelling not just at the astonishing preservation of an ancient landscape with scenes of hunting and butchery, but that it was all 500,000 years old – 200 millennia before we had thought early humans had first reached Britain. Five years ago the story moved round the coast from Sussex to Suffolk, where the discovery of tiny flint tools at Pakefield told us humans were here a further 200 millennia ago. Now that history has taken a third stride back for possibly yet another 200,000 years.
Yet at Happisburgh, it's not just the age that makes these finds so exciting. In fact, we're getting used to this rapid ageing, and there's every reason to think that before long we will be talking about early humans in Britain a million years ago. What has really surprised researchers – and was partly responsible for delayed publication of these new finds as earth scientists debated whether or not they'd got it right – is the context in which the pieces of flint were found.
The world in which these hominins lived was not one in which large game herds were on tap and in which the weather was always toasty – conditions archaeologists had come to accept as the basic requirements for early humans, the ones which limited expansion around the world once they had left Africa. Happisburgh has exceptional preservation of organic remains – not just bones, but insects' and plants' remains, including pieces of wood and pollen grains. All these describe a landscape and climate that was more like southern Scandinavia today than the Mediterranean.
The northern latitude contrasts with other Early Pleistocene archaeological sites, which all lie at least 8 degrees further south. As if to emphasise the significance of this, at Happisburgh the artefacts are not found at a time of deciduous woodland. They were made when conifer forest and grassland had replaced oaks as the climate cooled before an era when glaciers covered the land.
This undermines the traditional view that early hominins moved back and forth with herds of large mammals on which they depended for food, sticking to a warm climate. The new evidence suggests they were capable of adapting behaviour as the world changed around them. We have no evidence how they did this, but strategies must have included changes in how they gathered food.
The northern forests would have challenged a genus that hitherto had spent most of its time in regions less marked by seasonal change. At Happisburgh the hominins are likely to have eaten more plants in summer and more meat in winter – and then hunting or scavenging in shorter days, and sometimes extreme cold.
The key to survival may have been the mix of habitats around a river. We might imagine them not braving mammoth and bison, but collecting roots, shellfish and seaweed, and tracking grazing animals such as deer coming down to the water to drink.
And in the winter it got cold – several degrees colder than a modern winter in Norfolk. Surely they must have worn some clothing, and made artificial shelters. Perhaps, even, they had mastered the use of fire (charcoal was found at the dig, though we do not know what caused the wood to be burnt – it could come from natural fires).
The actual flint artefacts are rare, simple and small. But the story they tell is profound. Even this long ago, early humans were substantially cleverer than modern chimpanzees. And with a track record of underestimating early human capabilities, archaeologists are likely to turn up more finds to reinforce that view.
Mike Pitts is the editor of British Archaeology