Previously the oldest evidence for human settlement in northern Europe came from fossilized teeth and bones found in England and Germany.
Those remains are thought to belong to the species Homo heidelbergensis.
Stringer says there has been much discussion about what social, technological, or bodily adaptations such humans would have needed in order to colonize northern Europe from the south.
But, he said, "the climate reconstructed for ancient Pakefield suggests that these pioneers migrated north in an environment that would have been familiar to them, during a short warm interval."
Researchers say telltale traces of frost-sensitive insects and plants no longer found in Britain imply that the settlers enjoyed warm summers and mild winters.
The region would also have provided a resource-rich environment for Stone Age humans that supported many plants and animals, the study team reports.
An additional attraction "was the flint-rich river gravels, which would have provided the raw material for tool manufacture," Stringer said.
Severe, prolonged cold spells likely resulted in repeated interruptions to human occupation in northern Europe, Stringer says.
"We do not yet know whether the people at Pakefield were part of a population that gave rise to later heidelbergensis, or whether new people, bearing hand-axe tools, came into western Europe and replaced or absorbed the previous inhabitants," he said.
The first flints were found in a coastal cliff in 2000, triggering intensive searching, which has so far uncovered 32 artifacts in all.
The researchers say some of the flints remain razor sharp, despite the passage of 700,000 years, and that they all bear the hallmarks of human craftsmanship.
"The Pakefield evidence for human activity is rock-solid," according to Wil Roebroeks, professor of archaeology at Leiden University in The Netherlands.
In an accompanying Nature article, Roebroeks wrote that the stone tools flout the widely held view, based on evidence found in Spain and Italy, that there was a long lapse between the occupation of the Mediterranean region and the settlement of northern Europe.
The new finds, he added, "will surely influence our understanding of the human occupation of Europe."
"On a global scale, they are a reminder that we must be terribly careful with translating absence of evidence into evidence of absence."
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