Much of the 3,000-year-old wooden roadway or togher, discovered intact at Mayne Bog in Co Westmeath in 2005, was destroyed during commercial peat extraction over the summer.

An Taisce has criticised the National Monuments Service for failing to secure a preservation order for the Bronze Age site and is now calling on Heather Humphreys, the arts and heritage minister who has responsibility for the service, to make an urgent order on what’s left of it.

An Taisce’s calls have the backing of the recently retired director of the National Museum of Ireland, Patrick Wallace, who said of the road: “Its possible destruction would be an international calamity.”

The road was first spotted in 2005 and it was inspected that year by the National Monuments Service which arranged for a partial excavation the following year.

Those limited investigations found the road dated back to 1200BC-820BC and was made of planks of oak some 4.4m wide, running for at least 675m.

Despite its archaeological significance, and repeated requests from conservationists, it was never made a recorded monument or afforded the protections of recorded status.

Important Irish Archaeological Monument Being Destroyed During Heritage Week 2015 http://t.co/YdbHek7nlE pic.twitter.com/FgxzUWo6fs — An Taisce (@AnTaisce) August 28, 2015

A 2013 environmental impact statement for Westland Horticulture, which extracts peat on the lands, acknowledged the significance of the site but pointed out it was under no obligation to protect it.

It stated: “The trackway is not a Recorded Monument and hence peat harvesting activities have continued in this area leading to ongoing disturbance of the remains.”

Ian Lumley of An Taisce said in a letter to Ms Humphreys yesterday that the National Monuments Service “have accommodated the continued demolition of the monument”.

In a statement, the department said it was pursuing a preservation plan for what was left of the road in liaison with the developer. Mr Lumley noted that Ms Humphreys made a similar statement in reply to a parliamentary question last January and the destruction of the road still proceeded.