The former director of archaeological excavations at Carrickmines Castle has claimed recent work at the site was contributing to the "final destruction" of most of the castle remains.
Dr Mark Clinton, who headed the excavations at the site between 2000 and 2002, said the site was one of "national and international, cultural, historical and architectural importance", which needed to be preserved in situ.
His comments were contained in an affidavit read to the High Court on the opening day of a constitutional challenge to new legislation allowing for the partial demolition of the castle remains, which lie in the path of the last section of the M50 motorway, currently under construction.
The case, which has been brought by Mr Dominic Dunne, is challenging a section of the 2004 National Monuments Amendment Act, which allows the Minister for the Environment to issue directions relating to the removal or archaeological remains on or near the motorway route.
Last Thursday Dún Laoghaire Rathdown County Council gave an undertaking to the High Court to cease all but essential work on the site for a week, pending a full High Court hearing.
Work, including the removal of nearly 50 metres of stone fortifications or revetted fosse, had begun again on August 16th, on foot of new directions from the Minister, Mr Cullen. No work has taken place since January 2003, with the exception of a few weeks around Christmas last year.
According to Mr Clinton's statement, the recommenced work "can only be described as part of a process leading to the final destruction of a greater part of this national monument".
In written evidence for Mr Dunne, Dr Clinton said the site encompassed eight acres, although the actual castle remains, believed to be under an existing 18th-century farmhouse, had not been excavated. He claimed the existing remains had been "substantially interfered with" by the "extensive spreading of hardcore".
Excavations had also uncovered the skeletal remains of Confederate Catholics, who were massacred by English crown soldiers in 1642, he said. Some of the most important features uncovered during the archaeological investigation was the 217 metres of fosse, which he described as "unique".
Most of this would be removed or buried underground under the current proposals. The castle was part of the southern defence of what has become known as the Pale, he said.
In a replying affidavit, archaeologist, Mr Gary Conboy, the director of archaeology at the site, said all work was being carried out in accordance with professional standards and to the detailed directions of the Minister. It was "always acknowledged that the Carrickmines site is a significant archaeological complex", he said.
In relation to the fosse, everything was being recorded and taken down by hand in accordance with a process known as preservation by record.
In submissions to Ms Justice Laffoy, Mr Coleman FitzGerald SC, for Mr Dunne, said the plaintiff was challenging section 8 of the Act, which was introduced to deal with the Carrickmines site.
Mr FitzGerald said the section was unconstitutional as it gave the minister unfettered powers in relation to the removal and destruction of a national monument.
It was also unconstitutional as it did not provide adequate protection to the rights of citizens to the preservation of their heritage, and it did not comply with European directives regarding the protection of the environment and archaeological heritage.
The Minister for the Environment, represented by Mr James Connolly SC, rejected the claims. The State has also claimed that because Mr Dunne is not a landowner and had not made submissions at earlier planning stages, he did not have a right to take the current challenge.