Friends of the Victoria Lines have written to the Lands Authority asking for the entrances to the 'scarp galleries' at the Dwejra Lines to be secured to prevent further damage to them.
The Dwejra Lines are a scheduled heritage site that is government property.
These fortifications include six scarp galleries and a caponier, constructed to defend the ditch. They are all reached through tunnels from behind the line of ramparts.
The organisation said in its letter that these galleries were in a sorry state, their entrances had been forced open, they are full of litter and being used as toilets.
“It is imperative” that the entrances to the galleries and caponier are secured to prevent the ongoing abuse of this scheduled heritage site, they said.