Team saving Edinburgh Castle from a rocky horror show

EXPERTS have been drafted in to carry out work on Edinburgh Castle rock amid fears that large pieces of rubble could be ready to fall off. Specialist contractors are abseiling down the rock to carry out drilling on the north-west face below the Western Defences.

The work involves the removal of loose surface materials, such as roots and branches, which could increase the risk of rock falls.

David Storrar, regional architect for Historic Scotland, said: "The works we are doing now were identified a few years ago, but there are some pieces of rock which are potentially unstable and need urgent attention.

"I wouldn't say they were going to fall on anybody immediately, but the nature of the rock is that it is fractured through and through, so it's always liable to erosion.

"We try to be proactive but because the rock is really quite cracked, we will probably be doing this for evermore."

The work will involve larger pieces of rock being mechanically secured in place using stainless steel anchors.

The bolts can be up to four metres in length and require holes to be drilled into the rock.

Mr Storrar added: "This is an important rock maintenance operation involving a highly-trained team.

"We undertake rock-scaling operations such as this as part of an ongoing programme of conservation at Edinburgh Castle.

"This work is necessary because of natural erosion caused by wind, rain, ice and sunshine which can loosen the surface."

Built on the 340 million-year-old remains of an extinct volcano, Edinburgh Castle has suffered several rock falls in the past.

In 2006, a taxi driver had a lucky escape when a huge boulder fell and smashed into his vehicle.

Moments earlier he had watched as a tourist was hit on the head by a rock as she tried to flee the crumbling stones. Following the incident, Johnston Terrace was closed for two weeks.

Ben Harte, a professor of geology at Edinburgh University, said: "All rocks are subject to weathering and erosion over time, where time is measured on the scale of thousands of years.

"Rain and wind causes a chemical reaction with the minerals in the rock so that the rock crumbles on a very slow time scale. On vertical faces, rocks will fall off from time to time."

Last month, drilling began on the Castle Esplanade to find out if the centuries-old rock below can support the weight of a new grandstand for the Tattoo.

Bosses hope to secure funding for new grandstands, which can be put up and dismantled more quickly than at present.