Final preparations are underway for the judicial review of the Viking Energy windfarm, which is due to get underway tomorrow.
The hearing, called for by Sustainable Shetland, will sit in the Court of Session in Edinburgh and is expected to last up to four days.
Developers behind the 103-turbine windfarm, Viking Energy Partnership, will also be represented at the hearing.
The main legal argument being advanced by the protest group is that Scottish ministers should have ordered a public inquiry into the windfarm. They say ministers failed in their duties under the EU Birds Directive in relation to whimbrel.
Sustainable Shetland, which has nearly 850 members, has already secured a protective expenses order for the case.