The Auditor General found that no inspections to match waste materials arriving and leaving sites, or to verify waste on-site, have been conducted in the last two years.

Dorinnia Carville said she had identified “underlying operational challenges” facing the NIEA, including poor data collection and management information, and recruitment issues.

She said only two of the 36 legal cases taken in the past five years had resulted in environmental restoration by the defendant.

“The current operation of the inspection regime does not adequately identify or discourage criminality,” she continued.

“Legal enforcement activities, even when successful, rarely result in polluters remediating the damage caused.

“Furthermore, financial penalties through fines and confiscation orders are a fraction of the costs of dealing with the waste legally.”

She has recommended “a review of existing arrangements and inspection regimes” to ensure better value for money and more effective environmental protections for Northern Ireland.

The report points to the Mobuoy site, which the most reliable estimate suggests will cost £107m to clean up.

That cost is expected to “largely” fall to the public sector.