Archaeologists believe prehistoric Londoners were using the site to test, divide and prepare river cobbles used to make flint tools, before transporting them to another site to complete the tool-making process.
Crossrail Lead Archaeologist Jay Carver said: "This is a unique and exciting find that reveals evidence of humans returning to England and in particular the Thames Valley after a long hiatus during the Ice Age. It is one of a handful of archaeology sites uncovered that confirms humans lived in the Thames Valley at this time. The concentration of flint pieces shows that this was an exceptionally important location for sourcing materials to make tools that were used by early Londoners who lived and hunted on Thames Estuary islands."
