Analysis of the ecological impact of building a major new road scheme near landscape made famous by poet Seamus Heaney is not fit for purpose, the Court of Appeal in Belfast has heard.
Ornithologist Chris Murphy claimed the environmental assessment for part of the £160 million (€175m) A6 Belfast to Derry road was out of date, and the project would destroy the tranquility which draws migratory birds back every year.
But lawyers for the Northern Ireland Department for Infrastructure said surveys of whooper swan patterns on Lough Neagh and Lough Beg close to the disputed Toome to Castledawson stretch of road had been maintained annually.
Mr Murphy is seeking to overturn a ruling that the proposals do not breach a habitats directive on specially protected areas.
Reserving judgment on his appeal, Lord Chief Justice Sir Declan Morgan pledged to give a decision as soon as possible.
Mr Murphy’s legal case centres on plans to construct part of the road near Moosbawn, Co Derry, the childhood home of the late poet. The route was identified following a public inquiry nearly a decade ago. Former infrastructure minister Chris Hazzard gave the go-ahead to the scheme last year in a bid to significantly improve a major transport corridor and ease rush-hour gridlock.