30Secondly, it should be observed that Article 204 of the Customs Code is intended to ensure that the customs rules are correctly applied. Under Articles 96(1) and 204(1) of that code, the principal – in his capacity as holder in relation to the external Community transit procedure – is the debtor vis-à-vis the customs debt arising from the failure to observe the provisions governing that procedure. The liability thus imposed upon the principal is intended to ensure the diligent and uniform application of the provisions relating to that procedure and the proper functioning of transit operations in order to protect the financial interests of the European Union and its Member States (see, to that effect, Case C-230/06Militzer & Münch [2008] ECR I-1895, paragraph 48).