The north-south interconnector was first conceived in 2006 and plans to connect the electricity grids across the island of Ireland but has faced opposition from landowners both north and south of the border.

In 2017 the High Court rejected a challenge brought by North East Pylon Pressure Campaign against An Bord Pleanála’s decision to grant planning approval. The court also refused permission to appeal that judgment.

In Northern Ireland objectors were successful in 2019, the High Court quashing planning approval arguing that it required direct political oversight from a government minister.

The current judicial review was lodged before the court in November 2025.

The case challenges a number of decisions taken by the Department for Infrastructure regarding the discharge of pre-commencement planning conditions associated with the proposed construction of more than 100 electricity pylons carrying 400kV cables across 34 kilometres of countryside in counties Armagh and Tyrone.

The campaign group SEAT which represents over 6,500 residents and dozens of farmers, argues that the infrastructure should instead be placed underground or now reconsidered entirely, to avoid what they describe as unnecessary industrialisation of rural countryside.

Speaking ahead of the hearing, John Woods of SEAT said: “Northern Irish consumers pay highest electricity prices in Europe. A significant portion of the charges added to the electricity bills of each Northern Irish consumer is being used to fund the waste and mismanagement within the north south interconnector project. A project which has no discernible benefit to Northern Irish consumers or the wider Northern Irish economy, instead it is being built to facilitate the never-ending expansion of data centres in Ireland.”

“The north-south interconnector is a major infrastructure project carrying a substantial financial burden for Northern Ireland consumers. Before asking electricity customers to carry the significant costs, the NI Executive and Irish Government must come clean about what’s a stake.

“At the centre of that debate must be the rapid growth of data centres in Ireland, a growth which the north south interconnector, funded by Northern Ireland consumers, seeks to enable further.

“Other countries in the UK, Europe and the USA are now confronting the challenge posed by rapidly growing demand from very large electricity users. Denmark temporarily paused new transmission-grid connection agreements in March 2026 as demand from data centres drove increased demand which outgrew available capacity.

“The NI Executive and Irish Government therefore needs to explain clearly what kind of electricity system they are building, who it is building it for, and how it intends to ensure that Ireland’s and Northern Ireland’s consumers are not ripped off in the process. That debate should happen before more commitments are made, not after billions are wasted blighting some of Northern Ireland’s most beautiful countryside for generations with the now defunct north south interconnector project.”

The System Operator for Northern Ireland (SONI), which operates NI’s energy grid, did not comment on the legal proceedings, but told The Guardian in 2025 that remarks that the purpose of the interconnector was to power data centres were inaccurate, unfair and mischaracterised the interconnector.