text: In its turbulent 800 year history, Hay Castle has been besieged, set ablaze and become a frequent target for marauding Welsh rebels. But now the medieval stronghold that has already endured so much is at risk of falling to a new army of invaders… which each measure less than half an inch long. An infestation of deathwatch beetles is putting the imposing castle, which towers above the town of Hay-on-Wye on the Welsh border, at peril. Threat: Hay Castle is infested with deathwatch beetles burrowing in to its timber frames . A £5 million battle plan has been launched to repel the insect attackers, with structural engineers and historical building specialists hoping to repair the damage. The Hay Castle Trust, which is co-ordinating the renovation plans, has already received £500,000 from the Heritage Lottery Fund and will claim a further £4.9m once they have raised £1.5m from independent sources. Tests have shown the wood-boring beetles are active in the castle’s timbers. The damage is caused by their larvae, which burrow inside the wood, weakening them as they go. The adult beetles live for only a few weeks, but the larvae stage of their life cycle can last for up to 13 years. Hay Castle was built in the late 12th century by the powerful Norman Lord William de Braose and has been added to through the ages. Historic: But the 800-year-old mansion needs a major overhaul to eliminate the threat posed by the beetles . Project: Hay Castle has launched a fundraising drive to ensure its future in the fact of the insect threat . It was sacked by Llewelyn II, the last prince of Wales, in 1233, and rebuilt by Henry III. It was damaged by fire during the rebellion of Welsh chieftain Owain Glyndwr in 1401 and sacked again in 1460. The remains of the castle include a four-storey Norman keep and gateway, a Jacobean mansion was built alongside the tower in 1660, and Victorian terraced gardens. The rescue plan also includes tackling the rambling ivy which is further putting parts of it at risk of collapse after damaging the stonework. Juliet Aston, from historic building specialists Rick Mather Architects, said: ‘The most vulnerable part of the building is the derelict part of the mansion which hasn’t had a roof since 1939. ‘It’s hanging on by hook and by crook. Ivy is holding it together but destroying it at the same time. The walls are flapping about and are not stable. Invader: Deathwatch beetles like this one are living in the timber of the medieval building . ‘When the restoration project is finished it’s hoped it will be possible for visitors to stroll around the castle walls and enjoy a bird’s eye view from the top.’ The walls of the keep, are however, said to remain solid. The plans to restore the castle to its former glory include new driveways, cafe, restaurant, library, a study area and exhibition and display areas. Deathwatch beetles get their name from tapping or ticking sound often heard in the rafters of old buildings. The adult beetles make the noise to attract mates. It is said to be associated with the vigil kept beside dying people. The adult beetles measure 7mm long, and the larvae 11mm. The castle was since the 1960s owned by Richard Booth, the bookseller whose antics turned Hay on Wye in a ‘town of books’ and venue for a famous literary festival, until it was purchased in 2011 by the Hay Castle Trust.
target: Hay Castle on the Welsh borders faces infestation of deathwatch beetles .
  The 12th-century building is having its timbers weakened by the insects .
  Beetle larvae burrow inside the castle's wooden beams and threaten its structural integrity .
  Renovators launch £7million plan to save the historic castle .