For years, the predicament of many of the European protected habitats and species in the Flemish Region, as in many other Member States, passed relatively unnoticed. The lack of proper rules and clear implementation rules fuelled the impression amongst project developers and planning authorities that the impacts of project developments on biodiversity did not really warrant closer assessment. However, in the past ten years, strict national case law has significantly altered this view. Faced with tighter judicial scrutiny, the Habitats and Birds Directives were seen as an important obstacle to project development. Hence mitigation and compensation have now come up as novel approaches to better align spatial aspirations with the conservation of nature. In reality, mitigation was often used as a cover-up for projects that would not fit the strict requirements enshrined in the derogatory clauses. Interestingly, the Belgian Council of State showed itself quite cautious in reasserting the lax view of some planning authorities on mitigation and compensation. In reviewing the legality of several new approaches to mitigation and compensation, the Belgian Council of State, which was initially very cautious in quashing decisions that would actually jeopardise major infrastructure developments, has rendered some compelling rulings on the specific application of mitigation and compensatory measures in a spatial planning context. By letting the objectives of EU nature conservation law prevail in the face of economic interests, the recent case law of the Belgian Council of State can be seen as a remarkable example of judicial environmental activism.