A GROUP opposed to a massive power line planned to run between Meath and Tyrone have reacted with fury to a decision by An Bord Pleanála to grant permission.

The North East Pylon Pressure Campaign (NEPPC) said the decision was an “affront” to the democratic process and warned that legal action to halt the €300m project was likely both in Northern Ireland and the Republic.

The North South Interconnector involves construction of almost 300 pylons in Meath, Cavan and Monaghan, some up to 51 metres high, and was subject to some 200 objections on health and environmental grounds.

The high-voltage power line allows electricity to flow between north and south, and was part of the €3.2bn Grid25 project launched in October 2008. Permission was sought in December 2009, but withdrawn the following June.

A new application was lodged with the board in June 2015, and was subject to a public hearing which lasted for almost three months. It was approved this morning.

In its decision, the board said it had regard to the benefits of integrating both electricity grids, Government policy and the potential impact on the environment.

The board agreed with its inspector which recommended that permission be granted.

Fintan Slye, chief executive of EirGrid, said the North South Interconnector is "undoubtedly the most important infrastructure scheme on the island".

"(It) will also provide local benefit for the people of the north east by strengthening the electricity network in the region; a catalyst for inward investment and job creation," he said.

"The project will also increase capacity of the grids north and south, helping to facilitate the connection of more renewable electricity generation. This is essential to achieve sustainable energy targets set by the EU."

Speaking on RTÉ Radio One this lunchtime, he added: "We have a team of agricultural liaison officers and community liaison officers in place on the ground that have been and will continue to work

"The challenge for us is to work with those community organisations, with those land owner organisations. It is a critical piece of infrastructure that is necessary to support society and the economy and everyone benefits from it.”

EirGrid has said there was just one interconnector between both jurisdictions, and if a problem occurred it would result in widespread power failures.

But NEPPC, which claims to represent 45,000 households, said the lines should be constructed underground, and called on politicians to intervene.

“NEPPC is calling on all elected representatives to seek a solution to the impending impasse and conflict,” it said. “Time still exists for EirGrid to be directed to do the right thing and underground the project.

“The landowners and local communities are disgusted with how they have been treated for the last 10 years. If An Bord Pleanála think there will be no repercussions in terms of integrity of the planning process from this decision then they are gravely mistaken. If political action is not taken this project will make the Shell to sea debacle look like a walk in the park.”

Opposition to the line centres on a number of concerns including health, impact on the landscape, animal welfare and agriculture and biodiversity.

There was also widespread belief that the projects were imposed on local communities without adequate consultation, a claim EirGrid denies.

The line links a substation in Woodland, Co Meath with a new substation in Turleenan, Co Tyrone. It will more than double the power transfer capacity between north and south, improving efficiency and allowing more renewables onto the system.

The ESRI has suggested that the project would remove the cross-border bottleneck and reduce annual operating costs of the network by €30m a year.

EirGrid has also suggested that undergrounding the system would add €500m to the bill.