1.The measures referred to in Article 3 shall comply with the following principles, in accordance with the national law of the Member State:
(a)a prior hearing and right of appeal by the operator concerned in respect of the measures referred to in Article 3 (1) (c) and, where appropriate, (b);
(b)proportionality between the irregularity committed or suspected and one or other of the measures referred to in Article 3 (1), subject to the provisions to be established in accordance with the procedure laid down in Article 5;