Last year the charity successfully blocked the Scottish Government’s decision to approve the Stronelairg development, near Fort Augustus, at a judicial review hearing, claiming the required planning procedures regarding environmental impacts and objections to the project had not been properly followed.

The charity also claimed the project would be a blight on a “precious area of wild Scotland” which is home to a large area of peatland.

However, SSE and the Scottish Government appealed the judicial review decision, and won their case at the Court of Session in Edinburgh.

Now the Trust has abandoned its fight against the plans.

A John Muir spokesman said: “The decision to approve the scheme flew in the face of expert advice from the government’s own advisory body, Scottish Natural Heritage, which stated that the development would destroy the character of one of Scotland’s key areas of wild land.

“The application was also opposed by the Cairngorms National Park Authority, the Mountaineering Council of Scotland and three out of four local councillors, while written objections from the public outnumbered letters of support by 15 to one.

“Yet there was no opportunity for thorough public scrutiny of the proposal: because there was no objection from the relevant Highland Council planning committee, there was no requirement for a Public Local Inquiry.

“We believe that decision was based on flawed advice from planning officials.”

They added: “Fighting this battle has consumed a significant amount of time and money we have come to the conclusion that we have reached the end of the road with our legal action.”

Mountaineering Scotland - formerly known as the Mountaineering Council of Scotland - plans to donate £5000 to help the John Muir Trust cover its legal costs.

It will be responsible for paying part of SSE and the Scottish Government’s legal fees, although how much has not yet been decided.