The Court answered preliminary questions concerning article 6 of the Habitat Directive 92/43/EEC in relation to mechanical cockle fishing in the Dutch Waddenzee, a Special Area of Conservation. The Court explained that this activity falls within the concept of ‘plan or project within the meaning of Article 6(3) of the Directive. A plan or project likely to have significant effect on the site is only to be authorised if it is ascertained that it will not adversely affect the integrity of the site, i.e. where no reasonable scientific doubt remains as to the absence of such effects. In case of doubt, the precautionary principle as imbedded in article 6 (3) prevents the authorities from authorising the plan or project. The national court can determine the lawfulness of an authorised plan or project by assessing whether the national authorities have observed the limits of the discretion as set out in article 6(3), even when this provision has not been transposed into national legislation despite the expiry of the time limit. The provision has direct effect, in other words.