RPS, specialist consultants employed by the road designers to give environmental advice, carried out the evaluation, a combination of geophysics and excavation.
According to Canham, the geophysics showed nothing of significance but flints found on the surface meant the site warranted further investigation.
Excavation uncovered animal bones and 44 flint hand axes, the earliest tool used by man probably to divide animal carcasses.
Archaeologists believe the site would have been used as a seasonal riverside camp by hunters who lived in early Stone Age Britain.
"These finds appear to be of national significance. This is a very exciting discovery that has helped our understanding of the period", says Helena Cave Penny.
The archaeological report can be inspected at Salisbury Reference Library. The finds will be catalogued and many will be put on display in Salisbury Museum.
"The museum does have a collection of similar finds”, says Roy Canham, “but with no explanation or context about the environments and deposits in which they were found. This should be a very interesting contribution to the Salisbury collection."