PLANS to build the world’s biggest onshore wind farm on the Western Isles could be thwarted by European officials, who believe they breach laws protecting sensitive wildlife habitats.

The European commission believes that proposals to build more than 180 turbines on Lewis are flawed, because developers have failed to assess other less sensitive sites across Scotland.

The Lewis turbines, each more than 460ft high, would stretch for more than 25 miles through peatland protected under European Union conservation laws. The area is home to eight species of Europe’s most endangered birds, including golden eagles, red-throated divers and merlin.

Last week Lewis Wind Power (LWP), a joint venture between Amec and British Energy, submitted revised plans to the Scottish executive for the £500m project, reducing the number of turbines from 234 to 181 to lessen the impact on wildlife.

The company said it had restricted the search for sites to the Outer Hebrides because one of the primary aims of the project was to provide social and economic benefits to the islands.

The plans are now being scrutinised by the European commission.

The Sunday Times has learnt that officials in Brussels believe that the company must assess other possible locations across Scotland to comply with the habitats directive, which demands that other sites are considered when species and protected tracts of land are threatened by development.

The decision could have implications for other developments in Scotland, such as the wind farm at Waterhead Moor in north Ayrshire, which threatens a special protection area for hen harriers.

The European commission’s intervention is a blow for Jack McConnell, the first minister, who has set ambitious targets to produce 40% of Scotland’s energy from renewable sources by 2020. The Lewis wind farm alone would produce enough energy to meet almost 7% of this target. Energy would be transferred to the mainland through subsea cables.

It means LWP could, at best, be forced to spend tens of thousands of pounds and many months assessing other sites. But if commission officials conclude that Lewis is not the best location, they could demand that the plans are scrapped.

The Scottish executive would risk being taken to the European Court of Justice and could face heavy fines if it ignores the EC’s warning.

Last October the Portuguese government was fined undisclosed costs for building a motorway across a special protection area for birds and failing to consider alternatives.

“The trouble with the argument the developers have put forward is that it doesn’t actually stop them from looking at a wider area and I think that (argument) will not be accepted,” said a commission source. “It won’t wash.”

More than 4,000 people have opposed the Lewis proposal because they believe that the huge turbines will ruin protected peatland and could kill hundreds of rare birds.

Local residents have formed a campaign group amid fears that the wind farm will damage the local economy by costing the island up to £10m in lost tourism revenue and blight its picturesque countryside.

“Our starting point is that we think (the developers) should look as widely as possible and that means Scotland-wide,” said Neil Michison, head of the European Commission Office in Scotland. “That does not appear to be the case and this will have to be looked at very carefully.”

David Hodkinson, a director of LWP, said: “Our assessment focuses on alternatives in the Outer Hebrides because of the crucial role the Lewis wind farm would have in economic regeneration in that region.”

Anne McCall, head of planning and development for the Royal Society for the Protection of Birds in Scotland, welcomed the commission’s intervention.

“This is an absolutely massive development and our concern is that, if successful, this will open the floodgates for huge wind farms on important ecological sites all over Europe,” she said.

The Scottish executive said: “We have no comment to make on the Lewis application as that would prejudice a decision.”

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