Mountaineers and other outdoor groups hope Highland councillors will ignore the advice of their planning officials next week when they consider the controversial extension to an existing wind farm.

Falck Renewables Wind Limited want to add another 10 larger turbines to the 26 which currently operate as the Millennium wind farm in the hills between Glenmoriston and Glengarry to the west of the Great Glen.

The Millennium wind farm consists of 26 turbines, 16 of which are 377ft and 10 of which 410 m, both to blade tip. The proposed 10 'Millennium South' turbines would be larger at 433ft m to blade tip.

The final decision will be taken by Scottish ministers but Highland Council's Head of Planning and Building Standards, Ken McCorquodale, has advised members of the South Area planning applications committee, to "Raise No Objection". The council is an official consultee.

But Fort Augustus and Glenmoriston Community Council does object to the application not least because of the cumulative landscape impact with four wind farms consents within a radius of less than 10 miles.

Mountaineering Council for Scotland also objects because of the cumulative visual impact in an area of outstanding landscape importance. It argues the capacity of this area to absorb the environmental impact of wind farms has been exceeded.

The Scottish Rights of Way Society also has concerns over cumulative impact on recreational users of this countryside.

However the wild land charity the John Muir Trust raises different issues saying of the application "It does not on the whole significantly increase the impact of the existing structures with the exception of the new proposed access route from the south. This new route is not justifiable and could change access to the whole wind farm. "

The Scottish Environmental Protection Agency (SEPA) raised a similar objection. It particularly highlights the lack of justification for the proposed new 4x4 access track, which crosses peatlands.

Dave Gordon, Co-director for Landscape and Access with the Mountaineering Council of Scotland, said: "The MCofS objected to this application - the third for this wind farm - on the grounds of the cumulative impact of the density of turbines. Taken together with Beinneun wind farm and its proposed extension, this area will appear as a substantial mass of turbines particularly visible from classic mountains to the west and south.

"It is regrettable, but predictable, that Highland Council's planners would recommend no objection. This area is already an industrial site and intensifying development does less harm than a new development elsewhere. However, our worry is that we will continue to get both further development on existing sites and new sites being proposed, such as at Culachy, just across the Great Glen, where an application is imminent. Large chunks of the Highlands are losing their appeal to many mountaineers."

But Richard Dibley, Falck Renewables project manager, insisted: "This is an extension to an existing wind farm which will have very minimal visual impact. It is close to our UK operational headquarters from where we monitor all our European wind farms. The existing Millennium Wind Farm is located on a site which enjoys an extremely good wind resource and is well established and a very successful producer of electricity."