As the Court has already held (see judgment in Case C-172/89 Vandemoortele v Commission [1990] ECR I-4677), a penalty, even of a non-criminal nature, cannot be imposed unless it rests on a clear and unambiguous legal basis. It is therefore necessary to annul the Commission' s decision withholding part of the amount due to a tenderer in payment of supply in respect of food aid on the grounds of delay in delivery, when Article 18(2) of Regulation No 2200/87 provides for the withholding of part of that amount only where the goods or packaging do not correspond to the requirements and Article 22(2) of the same regulation provides for the possibility, which the Commission did not make use of in this case, of penalizing a delay in delivery by withholding part of the security on its release.