The environmental impact of the world's largest proposed onshore wind farm could be 30 times worse than expected, a peatland expert has warned.
The onshore development would be the biggest in Europe
A report commissioned by the Royal Society for the Protection of Birds says a massive wind farm on the Isle of Lewis could be "catastrophic".
Richard Lindsay, of the University of East London, said the developers had undervalued the quality of the habitat.
Lewis Wind Power Ltd said it would not comment until it had read the report.
RSPB Scotland has submitted a formal objection to the 234-turbine wind farm. About 5,000 have been lodged in total, opposing the plan.
Mr Lindsay, the university's head of conservation, said the wind farm on the Hebridean island could have a devastating impact on the internationally important peatland site and the environment as a whole.
He claims Lewis Wind Power Ltd has also hugely underestimated the area of carbon-rich peatland which could be affected.
An evaluation undertaken by Mr Lindsay indicates the impact of the proposed wind farm could be up to 30 times greater than that predicted in the company's own environmental statement for the site.
"We build wind farms in order to reduce carbon emissions, we then build our wind farms on peat," Mr Lindsay said.
"Yet peatlands represent the one land-based habitat that is a major long-term carbon store.
"By building the wind farm on peat, we release this carbon store as carbon emissions to the atmosphere."
He also points out that peat contains less solids than milk and that if it is built upon and disrupted, it can lead to catastrophic "bog slides" such as the recent one at a wind farm in Co. Galway, Ireland.
The report says the wind farm would put habitat at risk
In that incident, 2km of peat hillside poured down across the landscape for a distance of more than 20km.
In February this year, RSPB Scotland submitted its formal objection to the Lewis wind farm on the grounds of its likely impact on birds and the environment.
Commenting on Mr Lindsay's findings, the charity's planning and development manager Anne McCall said: "The findings of this report provide the final nail in the coffin for the Lewis Wind Power proposal.
"The RSPB strongly supports the need to tackle climate change and recognises that renewable energy developments will play a critical role in doing so.
"But it makes no sense to allow a development on a site which is highly valued by local people, internationally important for birds and made up of a highly sensitive peatland habitat."
The developers' environmental statement acknowledges that the development will result in the loss of at least 20 red-throated divers, 50 merlin and 50 golden eagles due to collision during the 25-year lifetime of the development.
It also says 350 pairs of golden plover and 314 pairs of dunlin will be lost to the population due to displacement.
The Western Isles Council meets next week to consider presentations from local communities and environmental organisations.