Billions of pounds of investment is at risk after RSPB Scotland mounted a legal challenge to four major windfarms in the firths of Tay and Forth.
The group confirmed it was seeking judicial review of the decision by Scottish ministers to grant consents for the Neart na Gaoithe, Inch Cape and Seagreen Alpha and Bravo arrays.
The developments have the potential to power more than 1.4 million homes and their construction would involve investment exceeding £7 billion.
RSPB Scotland said its decision to mount a court challenge had not been taken lightly.
“The RSPB only takes legal challenges that raise important issues of public interest surrounding the protection of the UK’s natural environment,” a spokesperson said. “Fortunately it is very rare that this is necessary and we have not had to take a legal challenge in Scotland for over 10 years.
“However, these decisions raise important questions about how the laws that are designed to protect our country’s most important places for wildlife, and the birds that depend on them, are applied.
“If these decisions are allowed to stand, they could have serious implications for how birds and important wildlife sites are protected across Scotland and beyond.
“The vast majority of renewable energy developments pose no significant threat to birds or other wildlife.
“RSPB Scotland continues to support the development of carefully sited and designed renewables, including offshore wind.”
Lindsay Leask of Scottish Renewables said the challenge was “disappointing”.
“Every one of these projects has been through an incredibly rigorous, detailed and independent assessment lasting anywhere between one and two years, and it now looks like there will be another lengthy examination of that process in court before they can go ahead.
“This action is now holding up two-thirds of the schemes in development around our coastline,” she said.
She added: “The irony here is that climate change is reckoned to be one of the biggest threats to Scotland’s protected habitats and species. Offshore wind is a key part of the mix required for us to meet our targets for the growth of renewables and the reduction of carbon emissions.”
A spokesperson for Seagreen said last night: “Seagreen is disappointed that our offshore windfarm consents have been challenged by RSPB and will respond to any legal challenge through the appropriate channels.”
A spokesman for Neart developer, Mainstream, said: “We are continuing our preparations for the development of the Neart na Gaoithe offshore windfarm.
“The project will bring hundreds of jobs to Scotland, contribute to the country’s energy security and deliver significant renewable electricity generation to help meet internationally-recognised climate change targets.”