In May, Scotland’s Inner House of the Court of Session backed ministers’ decision to reinstate 2014 consent for four large offshore wind farms in the Firths of Forth and Tay totalling 2.3GW.
The court’s Outer House had previously ruled in favour of the Royal Society for the Protection of Birds (RSPB), blocking the plans.
The charity this week applied to the UK Supreme Court in London for permission to appeal the most recent Inner House decision after an appeal in Scotland was rejected last month.
But following the most recent plea, 29 companies involved in the Neart Na Gaoithe (NnG) project, including lead developer Mainstream Renewable Power, formed the NnG Offshore Wind Farm Coalition to support the £2 billion (€2.19 billion) project.
The coalition has urged RSPB Scotland to withdraw its appeal.
RSPB Scotland director Anne McCall said the charity believed the Firth of Forth wind farms could lead to major declines in gannet, puffin and kittiwake numbers.
After making the application, McCall said: "Our concerns with the manner in which Scottish ministers took their decisions in 2014 remain undiminished.
"Additionally, the issues of the case and the recent Inner House judgement extend beyond simply the impacts of these developments on important seabird populations.
"Therefore, due to the implications of this latest decision for many aspects of our work we felt we had no choice but to apply to the Supreme Court."
The charity had also applied to question the Scottish Court of Session’s approval of the NnG site, but this request was rejected in July.
The NnG Offshore Wind Farm Coalition has today published an open letter urging the charity to withdraw its appeal and prevent further delays to the project.
Alan Duncan of Scotia Supply Chain, and a spokesperson for the coalition, said: "While we are sympathetic to the concerns of the RSPB about the planning process, this is about real people, real jobs and real environmental benefit.
"Scotland cannot afford to put nationally significant infrastructure projects like NnG at risk.
"We all work in the environmental power sector, developing projects like NnG which will help to combat climate change, protect our environment and create jobs.
"The project has sought to work with RSPB from day one and we are keen to continue to work together with them to increase industry understanding of how offshore wind assets and wildlife can successfully thrive together."
Neart Na Gaoithe is one of four wind projects consented in the outer Forth and Tay estuaries, but so far is the only one to be awarded a Contract for Difference (CfD) subsidy, meaning construction could start as early as next year, the coalition claimed.
