Customs and police officers have raided a diesel laundering plant at County Monaghan in the Republic of Ireland, close to the border with Northern Ireland.

The plant at Drumboat, Inniskeen, had the capacity to launder 20 million litres of diesel a year, equating to an annual loss to the Irish exchequer of 10m euros (£7.82m) in excise and duties.

One man in his 40s was arrested over breaches of environmental waste legislation.

Fifty litres of fuel, most of it laundered, was seized. In addition to a static laundry, customs officers also seized three oil tankers, one of which contained a mobile laundry.

The overnight operation was supported by armed police and a customs spokesperson described the seizure as “significant”.