Nullum crimen sine lege

The principle of nullum crimen sine lege forms the cornerstone of the legality principle in Dutch criminal law. It requires that conduct is punishable only where, at the time it occurred, a clear and accessible statutory provision existed that prohibited the conduct and attached criminal liability to it. This safeguards individuals against arbitrary state action and the retroactive application of criminal provisions.

The principle is enshrined in Article 1 of the Criminal Code and derives from Roman law. It guarantees legal certainty and prevents the authorities from imposing criminal sanctions on conduct in the absence of prior democratic legitimation.

In practice, the court determines whether the facts alleged in the indictment fall within the scope of an existing criminal provision. Where doubt arises as to the applicability of the law, the principle is applied in favour of the defendant.