THERE have been contradictory reports about an apparent oil leak at a controversial exploratory drill in Co Antrim located close to a reservoir used to supply homes with drinking water.

The Stop the Drill group, which has been campaigning against plans by InfraStrata to drill for oil at Woodburn Forest near Carrickfergus, said a "hydrocarbon spill" was observed over the weekend.

The Northern Ireland Environment Agency confirmed the leak and said inspectors had observed "evidence of a very minor mineral oil spillage which had entered a small waterway which runs across the InfraStrata site."

However, Northern Ireland Water claimed its inspectors who also visited the scene could "find no evidence of a spillage."

Northern Ireland Water, which leased the site to InfraStrata, has previously insisted that the project will not compromise the water supply.

Those objecting to the drill are concerned about the potential impact on water supplies provided by Woodburn reservoir to thousands of homes across Co Antrim.

In a statement on social media, accompanied by photos reportedly of the spill, Stop the Drill said: "The water course runs into Woodburn River and is in a water catchment area. A hydrocarbon was observed in the water course and a hydrocarbon slick covered the water surface.

The group added: "The various statutory bodies DoE, DETI, Mid and East Antrim Council and the landlord NI Water all appear to trust InfraStrata. On the other hand people who have genuine concerns have been accused of scaremongering."

The campaign group said it believed the leak was caused by an excavator being used to secure fencing on the site.

Stop the Drill also alleged that there had been a previous spill of hydraulic fluid by an InfraStrata contractor last month, but NIEA said it had not received reports of a previous leak on February 19.

Before Easter, campaigners took the first steps in challenging, through the courts, the decision to drill for oil announcing that Mid and East Antrim Borough Council had been issued with a letter as part of a "pre-action protocol for judicial review."

Exploratory drilling is expected to begin in May, the company has said.

A Department of Environment spokeswoman said: "On the evening of Sunday 27 March a number of calls were received via the NIEA emergency pollution hotline concerning a diesel spill in Carrickfergus.

"Inspectors attended the reported incident the following morning. The inspectors found evidence of a very minor mineral oil spillage which had entered a small waterway which runs across the InfraStrata site. There was no visible impact on site and the cause of the spillage is unknown."

However an NI Water spokeswoman said it found no evidence of any leaks.

"NI Water can confirm they were made aware of a possible oil spill on Easter Sunday evening. NI Water staff carried out an inspection of the site and adjacent watercourses and at that time could find no evidence of a spillage."

No-one from InfraStrata was available for comment.