Opponents of the development earmarked for ground on Spittal Hill claim it would be the biggest blot on the Caithness landscape of any turbine venture, present or proposed.

They are urging people to object to the 30-turbine scheme being spearheaded by a company set up by Tom and Steven Pottinger, who own Banniskirk Mains Farm.

The brothers insist they have addressed concerns about the development through changes made in the number, layout and siting of the turbines following three years of detailed studies. They have also revealed that discussions are under way with affected communities about financial spin-offs they stand to gain from the venture.

The turbines, each standing 110 metres high, are due to occupy 980 hectares of land, all to the east of Spittal Hill. Just two would be sited on Banniskirk Mains, with the rest on ground owned by seven other landowners.

Spittal Windfarm Opposition Group (SWOG) was set up in August 2004 to fight the plans. Spokesperson Diane Craven said yesterday that local people are only now appreciating the sheer size of the proposed wind farm.

"It's amazing how many people are not aware of just what is being planned," she said. "We spoke to people after they voted in Halkirk at last week's election and found about 150 who wanted to object, who for the most part didn't seem to know much about the proposal. Of those we spoke to in the street, I reckon 85 per cent said they didn't want it.

"This is bang in the middle of Caithness and these turbines will be clearly visible all over the county. You'll readily see them from Morven in the south to Dunnet Head in the north, and from Forsinard in the west to Castle Sinclair Girnigoe in the east.

"The visual impact will be enormous, especially when the cumulative effect of other schemes is added in."

Mrs Craven points out that the Spittal Hill venture is also close to the A9, the main tourist route into the county. She says she has a personal axe to grind as her house will be about 1000 metres from a turbine if the scheme gets the go-ahead.

SWOG also objects because of the adverse impact it claims the proposed turbines will have on local wildlife, particularly otters, bats and rare birds such as hen harrier, merlin and whooper swans.

The group further points to the existence of a broch and other important archaeological sites in the area, as well as forecasting that residents will have to put up with nuisance from the noise, vibration and shadow flicker caused by the turbines.

SWOG is encouraging people concerned by the development to attend a meeting in Halkirk's Ross Institute at 7.30pm on Thursday, May 24.

Tom Pottinger, who lives on Baillie Farm, Westfield, said that he and Steven - a solicitor in Edinburgh - first conceived the scheme in 1994. It has been subject to a number of detailed studies over the past three years.

The results of these, together with feedback from a public exhibition last summer, have led to four revisions. These include a decision to site all the turbines to the east of the hill, away from the A9. Mr Pottinger said: "The site is very much in the centre of Caithness, though there is not a lot of habitation to the east of the hill, where we plan to develop.

"In landscape and visual terms, we've had detailed studies carried out and the only view which the consultants believe there be a significant impact on is that from the north - from Bower down towards Spittal Hill."

Mr Pottinger revealed that talks have started up to establish how the local area can benefit from an annual dividend from the operation of the wind farm. On the current going rates for community benefit pay-outs, this would involve an annual payment of £170,000.

Mr Pottinger said: "We've been speaking to community representatives in Halkirk and Watten, not just about the operation of a community fund. That is the common way of doing it, but we're keen to see communities take an actual stake in the development. That would give communities more benefit."

Two of the turbine sites are in the Halkirk Community Council area, with the remainder in the area covered by Watten Community Council.

The £60 million to £70m application by Spittal Hill Windfarm Ltd will be determined by Scottish Executive ministers. The closing date for representations is June 1.