Thingummy
This requires clarification from the council. The route is an aincient one. The public footpath parallel with the A10 one field over tracking north is present on Openstreetmaps, oficial overlay, which is generated from official data,  but absent from Cambridgeshires computerised definitve map. That is very odd. Some clarification is needed, may be there was a stopping up order when the A10 was built.