Relic Find Halts Road Construction

A controversial plan to build a motorway through an Irish heritage site has come to a halt 24 hours after the transport minister turned the first sod on the project, following the unearthing of ancient relics on the site.

Archaeologists, who have been campaigning for years to stop the proposed M3 passing so close to County Meath's Hill of Tara, the ancient seat of the high kings of Ireland, were jubilant after excavators found the remains of an iron-age or bronze-age wooden henge, an extensive ritual site with underground passages.

The discovery of the enclosure at Lismullen reinforced calls by protesters who want the motorway re-routed from the Gowra valley, an area where there are prehistoric monuments pre-dating many Egyptian pyramids.

"Henges are generally used for ceremonial activity and this directly links the valley with the top of the Hill of Tara, where a similar henge was found," said Muireann Ni Bhrolochain, a lecturer in Celtic studies at Maynooth and a leading opponent of the M3.

Construction was scheduled to begin last year. The Roads Authority has blamed legal action by protesters for delays costing €1m (£680,000) a week. Building work had begun even though the National Trust for Ireland is taking a case to the supreme court that could block it. The National Museum in Dublin will assess the henge's historical significance.