Nuisance "nighthawkers" have been illegally hunting for treasure at a historically significant archaeological site in search of riches.

Tasburgh earthworks, 10 miles south of Norwich, is the latest Norfolk location to be targeted by the trinket-seekers who "devastated" the area with more than 20 large holes.

The site - which is managed by the Norfolk Archaeological Trust (NAT) - is home to a defensive fortification that can be traced as far back as the Iron Age, as well as evidence of Saxon settlers. 

Wymondham & Attleborough Mercury: More than 20 deep holes were dug by nighthawkersMore than 20 deep holes were dug by nighthawkers (Image: Natalie Butler)

Natalie Butler, NAT director, said: "It is absolutely devastating - none of our sites have been hit like this before.

"On first observation, I counted 22 holes but there is likely more. It looks like they have systematically worked across the whole site."

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Coins, pottery and other artefacts have been found in excavations over the years - likely what the treasure hunters were looking for. 

Nighthawking is the theft of archaeological artefacts from protected archaeological sites.

Wymondham & Attleborough Mercury: Tasburgh earthworks were targetedTasburgh earthworks were targeted (Image: Norfolk Archaeological Trust)

Natalie added: "Anything could have been taken which would have been of great historical value but it has now been removed from its historical context.

"It is so awful and I have never seen anything like this."

Anyone who may have seen something suspicious is asked to get in touch with the Norfolk Archaeological Trust and Norfolk Police.