The colonization of Eurasia by early humans is a key event after their spread out of Africa, but the nature, timing and ecological context of the earliest human occupation of northwest Europe is uncertain and has been the subject of intense debate¹. The southern Caucasus was occupied about 1.8 million years (Myr) ago², whereas human remains from Atapuerca-TD6, Spain (more than 780 kyr ago)³ and Ceprano, Italy (about 800 kyr ago)⁴ show that early Homo had dispersed to the Mediterranean hinterland before the Brunhes-Matuyama magnetic polarity reversal (780 kyr ago). Until now, the earliest uncontested artefacts from northern Europe were much younger, suggesting that humans were unable to colonize northern latitudes until about 500 kyr ago^5,6. Here we report flint artefacts from the Cromer Forest-bed Formation at Pakefield (52° N), Suffolk, UK, from an interglacial sequence yielding a diverse range of plant and animal fossils. Event and lithostratigraphy, palaeomagnetism, amino acid geochronology and biostratigraphy indicate that the artefacts date to the early part of the Brunhes Chron (about 700 kyr ago) and thus represent the earliest unequivocal evidence for human presence north of the Alps.