Historic Scotland says rockfalls are possible at Dumbarton Rock. Photo: Stephen Sweeney CC-BY-SA-2.0

Parts of the popular climbing venue where the UK’s toughest route was posted has loose rock which might be dislodged, a Government agency warned.

Historic Scotland said Dumbarton Rock’s stone is generally stable, but rocks may become detached.

The crag, on the banks of the Clyde, is home to Rhapsody, the E11 route completed by Dave MacLeod, has suffered from graffiti being daubed on its faces.

The rock is also home to Dumbarton Castle.

Plans for a clean-up by Historic Scotland prompted fears climbing holds could be damaged, but the agency worked with the Mountaineering Council of Scotland to ensure climbing routes were preserved.

Now, following a geotechnical survey by Historic Scotland, the organisation has warned loose rocks of varying size could become detached. It says this is unpredictable.

The agency said: “Signs warning of the danger of potential rockfall have been erected on the path at the base of the rock.

“Historic Scotland will carry out regular monitoring of the rock and will inspect and scale the rock, if required, every five years.

“This will form part of a rock management plan which is being compiled at present.

“A rock liaison group has been formed with local groups to discuss future management of the rock.

“The report also recommended relocating the path at the base of the rock. Historic Scotland is reviewing this with West Dunbartonshire Council and others.”