ENVIRONMENT Minister Dick Roche knew a month ago that the site of a possible pre-historic 'temple' had been unearthed on the route of the controversial M3 motorway.
The National Roads Authority alerted his department early last month that a pagan site - the size of three football pitches - dating from 3,500 BC had been discovered at Lismullen, Co Meath. It had not shown up in initial surveys.
Experts believe that the find could be one of the most significant archaeological discoveries ever unearthed here, and might be the site of a structure similar to Stonehenge but made with wood.
Yesterday the Tarawatch campaign alleged that Mr Roche had issued draft directions to preserve the site 'by record' - in effect, noting where the site was before destroying it to allow roadworks to begin.
The Government insists no decision has been taken on its future, made public just 24 hours after Transport Minister Martin Cullen turned the sod on the ?850m road project.
Last night it emerged that the Department of the Environment was notified of the discovery by the National Roads Authority (NRA) early last month, but failed to tell Mr Cullen before he took part in the sod-turning ceremony.
"It was reported early in April," a spokesman said. "We had to wait for a report from the NRA which came in the middle of the month. This is part of the normal process in that the minister is kept informed of what's going on."
Archaeologists said the site was most likely a wooden 'henge' used for ritual ceremonies.
It is also understood that a burial mound has been discovered, which was the final resting place of a woman of high status.
If confirmed, this is the first example of such an artefact found in Ireland.
"It's very ancient and is a wooden equivalent of Stonehenge," archaeologist with NUI Galway Joe Fenwick said. "It consists of a large enclosure, and a high-status burial chamber seems to have come to light. It's several hectares in size, you're talking about a massive complex.
"Because of their nature, these timber henges are very rare. You could count them on the finger of one hand. The timber rotted away a long time ago, but the features would be dug into the subsoil. It would take a large team digging for several months to excavate the site."
Opposition parties claimed that the motorway should have been re-routed away from the Tara Skryne Valley to avoid any historic sites.
Fine Gael asked how a combination of ?30m and 500 archaeologists could have missed the site.
"This situation would be hilarious if it weren't so serious," FG transport spokesperson Olivia Mitchell said.
"The entire M3 project has been brought to a crashing halt by the discovery of a four-acre archaeological site in its path."
The route had been "selected after many years of examination and excavation and after the NRA assured us this was a safe route in terms of archaeological significance".
The Tarawatch campaign said if a decision was made to preserve the site 'by record' it would seek a judicial review.
An Taisce called for a full scientific excavation of the site and reconstruction of the temple which would become a major tourist attraction.