They could have been on a family outing, a small group of adults and children ambling along the banks of a wide river estuary on the Norfolk coast.
But the footprints they planted in the mud at Happisburgh were left 800,000 years ago – the oldest marks made by human feet ever discovered outside Africa.
Scientists are now trying to understand the full implications of the find, the first direct evidence of our earliest ancestors in northern Europe.
Researchers were able to make digital records of the prints two weeks before they were destroyed by encroaching sea tides.
The footprints were exposed at low tide as heavy seas washed away beach sands to reveal elongated hollows in compacted mud.
“At first we weren’t sure what we were seeing,” said Dr Nick Ashton, of the British Museum in London. “But as we removed any remaining beach sand and sponged off the seawater, it was clear the hollows resembled prints, perhaps human footprints, and we needed to record the surface as quickly as possible before the sea eroded it.”
Analysis revealed a range of adult and juvenile feet, possibly five people in all. The scientists calculated their heights varied from three feet to 5ft 7ins.
“This height range suggests a mix of adults and children with the largest print possibly being a male,” said Dr Isabelle De Groote, a member of the team from Liverpool John Moores University.
A report on the discovery appears in the online journal Public Library of Science ONE.
At the time the footprints were made, Britain was linked by land to continental Europe. The Happisburgh site would have been on the banks of a wide estuary several miles from the coast. The surrounding landscape then was very different from that of modern Norfolk, with deer, bison, mammoth and hippo grazing along the river valley.
Professor Chris Stringer, head of human origins at the Natural History Museum, London, said: “These people seem to have become extinct in Europe by 600,000 years ago and were perhaps replaced by the species Homo heidelbergensis.
Neanderthals followed from about 400,000 years ago, and eventually modern humans some 40,000 years ago.”