HISTORIC Berkeley Castle is under siege from a mysterious hole-maker that has turned the great lawn into something resembling an honeycomb.

Small holes first began to appear on the lawn in August. But since then the problem has spread so that the lawn now looks more like a sieve than the approach to a castle.

Castle director Elizabeth Halls said the holes are a mystery to all involved.

"It has been going on for around eight weeks," she said. "We have no idea what is causing the holes. But more and more have been appearing."

CCTV cameras caught a woodpecker pecking at the lawn, but it is not thought the bird is the culprit.

Mrs Halls added: "There seems to be runs underneath so we think the woodpecker is just adding to the problem - not the main cause. "They are mouse-size holes, around an inch in diameter, so we think the most likely offender is a vole."

So far attempts to flush out the mystery hole-maker have not provided conclusive results.

"We have consulted three experts," added Mrs Halls. "A pest controller could not find the answer, our deer park manager tried to smoke out whatever was causing the holes, again to no avail."

Environmental group Just Ecology, which has carried out a study of the deer park, is also interested to find out what is making the holes.

Traps have been laid, but again the hole-maker has averted capture.

"Another trap box will be put down in the hope of discovering what is making the holes," said Mrs Halls.