The structure was not discovered through deliberate archaeological prospecting but through necessity, turning up during excavation work carried out as part of a flood relief scheme along the Nore.

Archaeologist Ian Doyle uncovered the site on the western bank of the river, directly underneath the existing John's Bridge and beside an abutment of a bridge that preceded it, built in 1772. What he found were two collapsed post-and-wattle fences, the kind of construction made by driving upright timber posts into a riverbed and weaving flexible branches between them to create a barrier. Together, the fences appeared to form a V-shaped fishtrap, oriented north to south, measuring roughly 4.8 metres long and 1 metre wide. The logic of such a trap is straightforward: fish moving with the current are funnelled into the narrowing apex of the V, where they can be caught or held. Radiocarbon dating of two timber samples from the structure returned dates of 755 to 400 BC and 755 to 403 BC, placing it firmly in the Later Bronze Age or early Iron Age. The structure did not end at the riverbank; it continued beneath the western bank, meaning more of it likely remains unexcavated in the ground. People were fishing the Nore in an organised, engineered way at this spot for a very long time before anyone thought to build a bridge there.