HARDY’S Monument is crumbling away due to erosion.

The famous West Dorset landmark has been closed to the public because wind and frost have eaten into the 72-foot tall structure.

Crumbling stonework fell from the Victorian structure days after the National Trust fenced off the site near Portesham.

Repairs on the landmark building are expected to cost more than £100,000.

Rob Rhodes, the National Trust’s head warden for West Dorset, said a detailed survey in March 2007 revealed that stones and mortar in the structure were being affected by erosion.

He said: “We’ve monitored it and kept an eye on it but then in December we noticed the damage was accelerating. The weather this winter has been very frosty and that’s made the damage worse.

“It’s such an exposed place with the south westerly wind and rain that it’s like being in a jetwash and the mortar that was used to build it is susceptible to frost.”

A recent survey showed around 50 stones are cracked and fractured and the mortar is weak and perishing.

Mr Rhodes said: “There haven’t been any injuries to anyone but I noticed that three large chunks of stone had fallen days after we put the fence up.

“We have to keep people away from it. We know that 3,000 people a year climb the tower to enjoy the views and many more – probably tens of thousands – like to visit for picnics near the tower.”

The closure will continue until the monument is fully repaired.

But Mr Rhodes said the work could not get under way until funding was found – and the National Trust had too many calls on its resources to guarantee when repairs could begin.

He added: “The big expense in a job like this is the scaffolding – it’s very expensive because we need such big scaffolding. That’s one reason why you can’t do minor repairs from time to time.

“The last big repair was in 1995 and that was major work that involved taking the top off and rebuilding it. That was when the public were able to have access for the first time.

“But there’s been 13 years of erosion since then.”

James Weir, National Trust building surveyor, said the mortar used in the original construction was contributing to the problem.

He said: “In the long term we’re going to need to re-point around 60 per cent of the monument, using a lime mortar that would allow water to evaporate through the joints themselves rather than through the stonework.

“Given the current economic climate we’re not able to put a timescale on how quickly the project can start or be completed.”