Building a new £160 million road through landscape made famous by poet Seamus Heaney would be like cutting away at a Rembrandt painting, the High Court heard today.
An ornithologist compared the wetland where migratory birds nest to the works of the Dutch Master as he challenged plans for the A6 Belfast to Derry upgrade to pass nearby.
Chris Murphy also branded Northern Ireland "the dirty corner of Europe" in dealing with environmental and conservation issues.
He is seeking to stop a section of the road being built near Mossbawn, Co Derry - the former Nobel laureate's childhood home - due to an alleged breach of a directive on specially protected areas (SPA).
Judicial review proceedings are examining ecological checks on the potential disturbance to wildlife on Lough Neagh and Lough Beg from the proposed Toome to Castledawson stretch.
The disputed route for the dual carriageway scheme was identified following a public inquiry nearly a decade ago.
With commuters regularly facing rush-hour gridlock, the intention is to significantly improve the transport corridor connecting Belfast to Derry.
Legal action commenced after Infrastructure Minister Chris Hazzard gave the green light to the scheme last year.
Mr Murphy, who is appearing as a self-litigant, claims a breach of the habitats directive giving protected status to the Loughs.
Further assessments have been carried out since the Department first made checks on the presence of nesting birds, badgers and bats, and to ensure minimisation of disturbance to whooper swans.
But it is still to be determined whether these actions were part of a fulfillment of the habitats directive obligations.
In court today Mr Murphy gave an unqualified assessment of the area's significance.
"This wetland area should have world heritage status," he told Mrs Justice Keegan.
He went on to claim a constant erosion is taking place.
"Bit by bit the habitat is being nibbled at, just like cutting the corner off a Rembrandt," he argued.
"How can you build a motorway through such a special place and not expect at least some residual adverse effect to remain?"
He described walking all the fields in the SPA during more than 30 years of bird watching.
According to Mr Murphy it represents the most important site for the rare Bewick's swan in Northern Ireland.
But their numbers have plunged from just over 500 back in 1991, the court heard.
The ornithologist claimed it was "ridiculous" to contend that only 2% of the 41,000 hectare site could be impacted by the road.
He also recalled his excitement at coming to Northern Ireland from Cambridge in 1984.
"I was proud to be in a country that protected its heritage," he said.
However, he alleged that the reality is different.
"In truth, everybody now knows that Northern Ireland, in planning, major conservation and the environment, is the dirty corner of Europe."
The case continues.