This article examines the actual application of European administrative soft law in light of the Dutch principle of legality. European administrative soft law is not legally binding. However, European administrative soft law can generate judicial binding effects for the Member States on the basis of the jurisprudence of the Court of Justice. Moreover, the research on the actual application of administratice soft law in the field of European subsidies shows that it can also have a 'de facto' binding effect for the Member Sates.

The (legal and actual) binding effects of European administrative soft law are problematic in light of the principle of legality, according to which binding norms must be laid down in hard law. The article argues that with the application of administrative soft law, three functions of the principle of legality (the principle provides legal certainty and legitimacy and serves as a safeguard against public authorities) are not sufficiently met. Several possible solutions that may resolve this tension are proposed.