A decision annulled by the administrative court is, according to established case law, unlawful from the moment it is taken. This is no different in a case where the permit has already been granted by operation of law after the expiry of the decision period. This was recently confirmed by the Supreme Court, in a case where an administrative body had wrongly refused a building permit.

The application was not in conflict with the zoning plan, and therefore wrongly refused, and in addition the administrative body had decided outside the applicable decision period. As a result of the latter, the permit was granted by operation of law at that time. The administrative courts established that the refusal decision was unlawful. In the subsequent procedure, a civil case against the administrative body, the applicant filed for compensation for the damage suffered by this unlawful decision.

The court did not have to assume, in the context of the legal requirement of causality, that the applicant would already have had a permit, absent the unlawful refusal after the expiry of the decision period. Liability may exist, even before the moment of the unlawful decision, if the administrative body acts unlawfully by not making a timely decision, or by not informing the applicant of the permit. However, those grounds were not relevant in this case.

In another case, the Supreme Court found that if the administrative court has ruled on a decision that is open to appeal, the civil court is bound by the judgment of the administrative court on the legality of that decision. When assessing a point of dispute that does not concern the validity of the decision, the civil court is not bound by the substantive considerations underlying the judgment of the administrative court on that decision.