The Royal Society for the Protection of Birds (RSPB) has applied to the Supreme Court for permission to appeal against the development of a wind farm which it argues would impact seabird colonies.
The charity mounted a legal challenge after the Scottish government consented to four developments in the Firth of Forth and Firth of Tay in 2014.
It won at first instance but lost on appeal after it was denied permission to appeal to the UK’s highest court by the Court of Session.
However, the RSPB has now applied directly to the Supreme Court for permission to appeal.
It has argued the project threatens Scotland’s gannet, puffin and kittiwake populations.
RSPB Scotland director Anne McCall said: “RSPB Scotland has not taken this decision lightly, however 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 judgment 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.
“We are hopeful that our application is successful and that we are granted leave to appeal so these important issues of public interest can be considered in detail by the Supreme Court.”
A Scottish government spokesman said: “We note the RSPB’s decision, which comes after the Court of Session in Edinburgh ruled, decisively, in favour of Scottish ministers and subsequently dismissed the RSPB’s application for permission to appeal to the UK Supreme Court.
“The Scottish government is focused on creating a sustainable energy future for Scotland so that Scotland can meet its obligations to fight climate change, and thereby tackling a key threat to marine ecosystems.”