Continued unauthorised dredging of up to two million tonnes of sand a year from Lough Neagh is making a mockery of Northern Ireland's planning regime, the Court of Appeal heard today.
Counsel for Friends of the Earth also claimed the continued extraction represents a flagrant breach of ecological directives.
Judgment was reserved in the group's renewed legal bid to force a halt to the practice at the UK's largest fresh water body.
In 2015, former Environment Minister Mark H Durkan served enforcement notices on companies dredging sand from the Lough without planning permission.
His decision led to the firms lodging an appeal with the Planning Appeals Commission (PAC), and enabled them to continue their activities.
Friends of the Earth launched judicial review proceedings, claiming Mr Durkan should instead have ordered an immediate stop to all extraction.
Last year the High Court rejected claims that the Minister's decision effectively amounted to giving consent by "turning a blind eye" to the dredging.
But the group now want appeal judges to overturn a finding that there was legal authority for Mr Durkan's decision.
Its barrister, Gregory Jones QC, argued that the Minister failed to properly apply the precautionary principle of taking preventative action until definitive evidence of no environmental harm is secured.
"Our position is that this is actually a straight-forward, flagrant breach of the EIA (Environmenal Impact Assessment) Directive and the Habitats Directive," he contended.
"This case involves the ongoing and unauthorised commercial extraction of millions of tonnes of sand and gravel from a site that's both nationally and internationally recognised."
Sand traders have been carrying out extraction work on the Lough, a designated Special Protection Area due to its wintering population of birds, since the 1930s.
No planning permission for dredging has ever been sought or obtained.
Mr Jones argued that any holes created cannot be refilled.
"Every time a scoop is taken it ends up in someone's patio in Enniskillen, or Liverpool. You can't put it back."
The Minister did not have the discretion to weigh jobs in unauthorised sand extraction against potential damage to a protected area, the court heard.
Urging the appeal judges to call a halt to the dredging, Mr Jones said: "We ask the court, belatedly as it is, to put a stop to what is a mockery of the system here."
Tony McGleenan QC, for the Department, responded that a stop notice was neither mandatory nor the only option open to the Minister.
Although an enforcement notice was issued, he retained the power to intervene to stop dredging at a later stage if necessary, counsel insisted.
Mr McGleenan added that reasoned analysis was given to competing interests, with advice indicating no evidence of any environmental harm.
The dredging companies have spent £500,000 on studies to back their case that they are causing no damage to the Lough
Counsel for the firms stressed there was nothing to demonstrate harm being caused to birds, fish or habitats.
He also rejected any suggestion that his clients were attempting to delay resolution of the case.
Following submissions Lord Chief Justice Sir Declan Morgam sitting with Lord Justice Weatherup and Mrs Justice Keegan, pledged to deliver judgment as soon as possible. ends