FORAGING boar have turned over the grassy banks next to the 'Roman Road' at Blakeney Straits leaving a path of destruction in their wake.
A protective bank built by volunteers to keep the remains from traffic damage has been completely flattened to the level of the adjoining modern road.
The soil on the bank is not compacted like the surrounding ground and is an easier target for the mooting boar.
Other sections of the bank are thought to date back to the time the road was constructed or perhaps later as a division between sections of woodland, but are assumed to be at least pre-Napoleonic.
Local historian Brian Johns said: "The damage is very extensive and the pigs have even got their snouts in between the stones.
"At this point the paving ends because the rest has been washed away by flooding.
"Once they get the paving open they will be able to work right along the road pulling it up."
The bank was built by volunteers in the 1990s to protect the road from traffic and it was thought that fencing the area off might damage the underlying archaeology.
He said that boar tend to visit the same areas each year and it was likely that this would become a regular destination for the pigs.
"It is not the first time the boar have been here," Mr Johns said.
"I believe the Forestry Commission is aware of the issue and are working on a solution. Unless something is sorted out, there is an outside risk of losing the road."