Dublin City Council was misinformed by senior officials about the vintage of a building in Moore Street which served as the last headquarters of the 1916 Rising, An Taisce said yesterday.
The councillors were told that the building, which is scheduled for demolition, dated from the 19th century. However An Taisce has verified that it actually dates from the early 18th century.
No 16 Moore Street - now dubbed "Ireland's Alamo" -- was visited at the weekend by Dr Arthur Gibney, former president of the Royal Institute of the Architects of Ireland and an expert on 18th-century structures.
Following an inspection in the company of representatives An Taisce and the National Graves Association, which also wants to save the building, Dr Gibney said it "undoubtedly belongs to the first part of the 18th century".
This finding, based on the presence of diagonal chimneybreasts, conflicts with an assessment given to the City Council which indicated that the building was Victorian and therefore of "limited historical significance".
A spokesman for An Taisce said it was clear that the decision to demolish the building to facilitate development of the Moore Street frontage of the Carlton site on O'Connell Street was based on inaccurate information.
He said this should lead to a revision of the authenticity and significance of the building. If it was demolished, such an act would "parallel the destruction" 20 years ago of Robert Emmet's home in St Stephen's Green.
"Are we going to allow the same fate to beset No 16 as occurred with Emmet's house? If ever there was an epitaph to commemorate the 200th anniversary of Emmet's rising and subsequent death, this should not be it."
Dublin City Council however remains adamant that the entire terrace of buildings including No 16 - described by one source as "architecturally worthless" - must be demolished to make way for a new shopping mall.
Like other properties in the area, it had been bought by the Carlton Group, which subsequently failed to proceed with approved redevelopment plans. The entire site is now being compulsorily acquired by the council.
Though some of the interiors may date from the 18th century, the façade of No 16 Moore Street was replaced following the 1916 Rising. This might also explain some of the confusion over the building's provenance.
Proposals are being considered for a suitable memorial on the site, possibly in the form of a meditative space, as the council maintains that the GPO will always be the principal focus for commemorating the 1916 Rising.