Customs officers have raided an oil laundering factory during an intelligence-led operation in Co Monaghan this morning.

Officers, backed up by gardaí, raided a disused mushroom grow shed in Clontibret.

Inside they found a laundering operation capable of processing 2m litres of diesel a year, costing the Exchequer €1m in lost revenue.

A car and a van were also seized during the operation, however no arrests were made and the operation is ongoing.

Eight tonnes of toxic sludge was also found in the shed.