Conservationists and campaigners claimed victory last night after the Court of Session overruled Scottish Ministers and refused consent for a giant windfarm in the Highlands.
The 67-turbine Stronelairg development, which would have covered an area roughly the size of Inverness, was approved last year.
But the John Muir Trust brought a judicial review against the decision – which found in their favour yesterday.
Scottish and Southern Energy (SSE) had planned to build the windfarm at the Garrogie Estate in the Monadhliath mountains above Fort Augustus.
The JMT raised concern about the impact of the development on peat land and tourism to the area.
A number of individuals and groups such as The National Trust for Scotland and the Mountaineering Council for Scotland also backed the trust’s legal challenge.
Yesterday, Court of Session judge Lord Jones described the government’s decision as “defective”.
One of the points in his decision was that the government had not referred to an objection on principle by Scottish Natural Heritage when reaching the decision.
JMT chief executive Stuart Brooks described the plans as “the wrong development, of the wrong size and in the wrong place” while local campaigners also hailed the decision.
SSE said it was “disappointed” by the ruling, while the Scottishgovernment said it was considering its position “with a view to appealing”.
Mr Brooks said: “This is great news for all those who love Scotland’s wild land and wish to see it protected.
“A financial appeal brought a tremendous level of support from over a thousand well-wishers, allowing the Trust to proceed. Lord Jones has now decided the Trust’s court action was well-founded.
He added: “Lord Jones rightly identified that this case was taken and won in the public interest so the right thing for Scottish ministers to do is not to appeal this decision.
“The company now has an opportunity to show that they are listening to communities and tourism bodies and to engage with others to revitalise the natural environment rather than pursue this damaging development which would cover a footprint the size of Inverness.”
Legislation dictates that the ministers are prohibited from granting consent unless they have taken into consideration the environmental information provided by the likes of SNH and confirm in their decision that they have done so.
Lord Jones found that the JMT had “suffered prejudice as a result of the ministers’ failure to give reasons”.
Highland Council did not raise any objections to the decision when it was consulted.
Highland anti-windfarm campaigner Lyndsey Ward said: “This decision to set aside the Scottish Government’s approval of the potentially devastating Stronelairg wind farm is a victory for campaigners everywhere and for common sense.
“It shows that big guns like SSE are not invincible and can be silenced.
“This decision is not only a wake-up call to the Scottish government to make sure decisions are legitimate, but should encourage those who wish to stop environmentally damaging wind farms to take their fight all the way if they have a good case, as the JMT clearly did.
“If SSE want to continue with their attempts to despoil the hills around Loch Ness, against the clear advice from SNH, they will have to accept the rule of law and start from scratch.”
A spokeswoman for SSE said: “We are disappointed with the result of the judicial review of the consent decision for Stronelairg wind farm. We will now review the judgement in detail and consider our options accordingly.”
A spokesman for the Scottish Government said: “We have received the judgement of Lord Jones in relation to the petition lodged by The John Muir Trust for the Judicial Review of the Scottish Ministers’ decision to grant consent to construct and operate the Stronelairg wind farm, Garrogie Estate, Fort Augustus.
“Scottish Ministers are considering the terms of the judgement carefully with a view to appealing.”
It is understood that any appeal would be held in the second chamber of the Court of Session.