INTERNATIONALLY-acclaimed sculptor, Maurice Harron, has branded restoration work at Grianan Fort as "a gross act of cultural vandalism".
Mr. Harron - who designed, among other things, the iconic "Hands Across the Divide" sculpture at Carlisle Circus in Derry - says that, as a result of the ongoing renovation works, the historic monument has dramatically changed shape.
The restoration work, he insists, should stop immediately and expert stone masons brought in to "try to undo the damage already done."
However, the Office of Public Works (OPW) - which is overseeing and carrying out the work - insists its "intervention" will not only considerably improve the future stability of the monument but also ensure safe public access to the site.
The OPW says its conservation design team at the Grianan of Aileach site includes specialist archaeological and engineering consultants and that all work is being overseen by an expert team from its Heritage Services branch.
Maurice Harron, however, maintains that the original loose-stone technique used to construct the pre-Christian stone fort - known as corbelling and giving the structure its "wonderfully subtle curved wall surface" - has been abandoned "and the walls are now being knocked down in 15 foot sections and rebuilt flat and straight."
As a result, says Mr. Harron, "the round fort of Grianan is now a polygon."
"This is a gross act of cultural vandalism," he added. "There is no blame on the workers themselves but those who planned and are supervising this carry-on deserve to be criticised.
"They are using contemporary building techniques and materials presumably in an effort to make the building more safe and functional. Grianan of Aileach was not built to be 'safe and functional'. It is an extraordinary, evocative structure which has survived for more than two thousand years.
"It is one of our most direct connections with Celtic and Gaelic pre-Christian Ireland. It is one of the few structures or buildings not destroyed in the English Plantation and cultural obliteration of the 17th century.
"Can you imagine, for example, if France's Office of Public Works decided to renovate Chartres Cathedral – you can just hear them: 'we can get rid of the oul stained glass windows and put in some nice double-glazed windows and we can take down some of that stone work and put up concrete walls and some handy stud walls in the interior!' I don't think so.
"This renovation work should stop now. Get rid of the JCB, the concrete and cement. Employ stone masons willing to build in the original technique and style who can try to undo the damage already caused."
In response to Mr. Harron's concerns, the OPW in Dublin revealed that, following a series of major collapses, the monument was placed in State care in 1904.
A spokesperson said: "Local repairs were carried out at the time but, due to the unsatisfactory nature of the restored external masonry works and rubble/earth centre fill, sectional collapse continued at regular intervals."
He added: "A specialist structural engineering and archaeological survey undertaken by OPW in 2001 revealed the lower 'original' sections of wall and confirmed the reasons for the monument's instability. The original inward leaning and stable profile and line of the Grianan wall was established and the monument is now being restored to that design."
Referring to the "corbelling" technique alluded to by Mr. Harron, the OPW said it was a term that "would not normally be associated with external dry stone walling."
"Perhaps, the reference is to the modern unstable bulges in the walling which was, in effect, a warning of imminent collapse," said the spokesman.
"The present intervention should considerably improve the future stability of the monument and ensure safe public access to the site," he concluded.