11 DE CUBBER v. BELGIUM JUGDMENT which the procureur du Roi is empowered to take" (see paragraph 15, second sub-paragraph, above). In addition to this, as an investigating judge he has very wide-ranging powers: he can "take any steps which are not forbidden by law or incompatible with the standing of his office" (see paragraph 17 above). Save as regards the warrant of arrest issued against the applicant on 5 April 1977, the Court has only limited information as to the measures taken by Mr. Pilate in the circumstances, but, to judge by the complexity of the case and the duration of the preparatory investigation, they must have been quite extensive (see paragraphs 8 and 12 above). That is not all. Under Belgian law the preparatory investigation, which is inquisitorial in nature, is secret and is not conducted in the presence of both parties; in this respect it differs from the procedure of investigation followed at the hearing before the trial court, which, in the instant case, took place on 8 and 22 June 1979 before the Oudenaarde court (see paragraphs 12 and 15 above). One can accordingly understand that an accused might feel some unease should he see on the bench of the court called upon to determine the charge against him the judge who had ordered him to be placed in detention on remand and who had interrogated him on numerous occasions during the preparatory investigation, albeit with questions dictated by a concern to ascertain the truth. Furthermore, through the various means of inquiry which he will have utilised at the investigation stage, the judge in question, unlike his colleagues, will already have acquired well before the hearing a particularly detailed knowledge of the - sometimes voluminous - file or files which he has assembled. Consequently, it is quite conceivable that he might, in the eyes of the accused, appear, firstly, to be in a position enabling him to play a crucial role in the trial court and, secondly, even to have a pre-formed opinion which is liable to weigh heavily in the balance at the moment of the decision. In addition, the criminal court (tribunal correctionnel) may, like the court of appeal (see paragraph 19 in fine above), have to review the lawfulness of measures taken or ordered by the investigating judge. The accused may view with some alarm the prospect of the investigating judge being actively involved in this process of review. Finally, the Court notes that a judicial officer who has "acted in the case as investigating judge" may not, under the terms of Article 127 of the Judicial Code, preside over or participate as judge in proceedings before an assize court; nor, as the Court of Cassation has held, may he sit as an appeal-court judge (see paragraph 19 above). Belgian law-makers and caselaw have thereby manifested their concern to make assize courts and appeal courts free of any legitimate suspicion of partiality. However, similar considerations apply to courts of first instance. 30. In conclusion, the impartiality of the Oudenaarde court was capable of appearing to the applicant to be open to doubt. Although the Court itself