Campaigners against plans to remove parts of the medieval Carrickmines Castle in South Dublin have threatened legal action against the Minister for Environment.
It is proposed to remove the Castle site to facilitate the completion of the M50 motorway.
Minister Martin Cullen is currently considering a request from Dun Laoghaire-Rathdown County Council for consent to resume work on the site.
This comes despite the fact that the High Court is due to consider whether or not it is a National Monument.
Mr Cullen's decision - expected early next week - would make the High Court case redundant if he allows the work to go ahead.
