6.  The applicant was born in 1961 and lives in Beveren. 7.  On 10 May 2006 the Hasselt public prosecutor, pursuant to Article 28bis § 2 of the Code of Criminal Procedure (“CIC”), gave prior written agreement for the instigation of a proactive investigation against the applicant and several other suspects, on suspicion of drug trafficking, involvement in an international criminal organisation and money laundering. The proactive investigation included using the special investigative method of infiltration. On 1 August 2006 the public prosecutor also authorised the use of the special investigative method of observation. 8.  Pursuant to Articles 47septies § 1 and 47nonies § 1 CIC, a separate confidential case file was established (see paragraphs 47-49 below). 9.  The proactive investigation continued until 17 September 2008. On that date a report was drawn up by the police officer in charge summarising all the evidence gathered, summarising all the evidence gather in the framework of the proactive investigation. That report was followed by two more reports on 18 September 2008, one on the infiltration and the other on the observation operation, describing the evidence specifically gathered by means of those two special investigative measures. The three reports were added to the criminal file, which was subsequently to be made accessible to the defendants. 10.  By two decisions issued on 18 September 2008 the public prosecutor confirmed that authorisations had been given for both the observation and the infiltration operations. 11.  On 18 September 2008 the public prosecutor requested the investigating judge of the Hasselt Court of First Instance to instigate a judicial investigation. A “traditional” reactive investigation ensued, conducted by the investigating judge. In addition to the observation and infiltration operations, recourse was had to phone-tapping and international mutual legal assistance. 12.  A report drawn up on 25 September 2008 by the police officer in charge mentioned information on the existence of a criminal organisation which had served as the grounds for using observation and infiltration at the proactive search stage, as well as the confirmations obtained in the framework of the said special investigative measures. 13.  On 20 October 2008 the Federal Prosecutor’s Office took over the case from the Hasselt public prosecutor. The investigation remained under the oversight and authority of the Hasselt investigating judge. 14.  The observation and infiltration operations ended on 14 June 2009. On that date several suspects, including the applicant, were arrested and placed in pre-trial detention. 15.  By written submissions of the Federal Prosecutor of 29 December 2009, the Indictments Division of the Antwerp Court of Appeal was instructed to verify, pursuant to Article 235ter CIC, the conformity of the confidential file with the evidence contained in the criminal case file and to ensure that there were no irregularities (see paragraphs 50-54 below). During the proceedings, the parties requested that the court also verify the lawfulness of the procedure followed under Article 235bis CIC (see paragraph 55 below). 16.  At a hearing on 2 March 2010 the Indictments Division heard the Federal Prosecutor separately, in the absence of the parties. On that occasion, the confidential case file was made available to the Division. Subsequently, several defendants, including the applicant, were invited to present their case, assisted by their lawyers. 17.  By interim judgment of 20 May 2010, the Indictments Division stated that, as regards the scrutiny of the special investigative measures, it had to verify the information in the confidential file concerning not only the reactive investigation but also the proactive one. It further held that some evidence concerning the special investigative measures had yet to be added to the criminal file. It ordered the reopening of proceedings so that the Federal Prosecutor’s Office could complete the files. 18.  Following that judgment, the aforementioned decisions of 18 September 2008 and the report established on 25 September 2008 (see paragraphs 10 and 12 above) were added to the criminal file pursuant to Articles 47septies and 47novies CIC. 19.  By judgment of 24 June 2010, the Indictments Division declared the criminal file complete, stating that no nullity, irregularity or violation of legal or Convention provisions had been found (see Article 235bis CIC), and that no irregularities had been committed in implementing the special investigative methods (see Article 235ter CIC). 20.  As regards in particular the use of those methods during the proactive investigation, the division stated the following:
“The proactive investigation, including the special investigative methods of observation and infiltration, fulfilled the conditions of Articles 28bis, 47sexies and 47octies of the Code of Criminal Procedure. The strong prima facie evidence of the offences charged and the reasonable suspicion as defined in Article 28bis of the Code of Criminal Procedure were present, transpiring [from the reports of 25, 17 and 18 September 2008].
Those reports of 17 and 18 September 2008 also confirm that the ‘maximum’ limit of the proactive investigation was complied with. It was thus found, on the one hand, that the overview of the case had been sufficiently established, and on the other, that sufficiently serious indications had been obtained to instigate a reactive investigation. Those serious indications had been reflected in the summary written conclusions in response from the public prosecutor’s office. In that context, the discovery on 15 August 2008 of a debit indicator left by V.W. had been decisive.
The reports in question demonstrate that the special investigative methods used during the proactive investigation met the conditions of proportionality and subsidiarity.”
... 22.  The applicant lodged an appeal on points of law against the judgment of 24 June 2010. That appeal was dismissed by judgment of the Court of Cassation on 21 September 2010. Relying on Article 6 of the Convention, the applicant complained that the criminal file contained neither the report on the basis of which the public prosecutor had instigated a proactive investigation on 10 May 2006 nor the documents relating to that proactive investigation. Those pleas were dismissed on the grounds that they required a factual assessment which the Court of Cassation was unable to conduct. 23.  By order of the Hasselt Court of First Instance sitting in private session on 29 September 2010, seventeen defendants, including the applicant, were committed to stand trial. 24.  On 16 March 2011 the applicant was sentenced to ten years’ imprisonment and fined 137,500 euros by the Hasselt Court of First Instance for drug trafficking, involvement in an international criminal organisation and money laundering. It transpires from the almost 160-page judgment that the establishment of the facts stemmed partly from evidence gather by means of the special investigative methods.
... 27.  As regards the applicant’s request for a face-to-face meeting with the undercover agents, the court ruled as follows:
“Having regard to the procedure followed, to the proceedings relating to the special investigative methods implemented in the Indictments Division from the judicial investigation to the hearing stage, to the evidence before us, to the fact that two undercover agents drew up a report and that their results were compared, to the fact that the defendants were able to call witnesses and therefore, in particular at the request of the [applicant] and the second defendant, witnesses were heard in connection with the [applicant’s] statements on the undercover agents, and to the fact that the court and the defendants were able to compare the reports on the evidence gathered by the undercover agents with such objective facts as the items discovered during the searches (e.g. the card), the conversation between the undercover agent Billy and the [applicant], SMS messages (e.g. between the [applicant] and Billy) and telephone conversations (e.g. the conversation with the third defendant), the court considers it unnecessary for the establishment of the truth, the exercise of the rights of the defence and the safeguard on a fair trial for the undercover agents to be heard.
...
Furthermore, regard must be had to the aspect of the undercover agents’ safety and security and the importance of anonymity, inter alia from the angle of their possible involvement in other cases. In the present case this aspect is especially important given that the infiltration continued over several years and that friendly links had grown up between the agents and several defendants and their partners. During the preliminary investigation photographs of the undercover agents were apparently published on the Internet to alert others to their undercover status. In view of the friendships formed and the content of certain telephone conversations (including those between the [applicant] and the third defendant) ... the risk of reprisals is very real.
...
Lastly, it should be noted that it is unclear what specific questions they wish to put to the undercover agents. The [applicant] and the second defendant only wish to put questions to the undercover agent Billy concerning the recovery of the debit indicator allegedly thrown away by the [applicant]. However, since the undercover agent’s submission on this point is set out in the report included in the criminal file it is unnecessary to hear the undercover agent on this question. The Indictments Division, which is an independent tribunal, held that the reports corresponded to the confidential file. The defendants have an opportunity at the hearing to put forward their pleas concerning the recovery of the debit indicator and to contradict the undercover agent’s version.” 28.  The court replied to the applicant’s plea that he had been unable to verify whether an undercover agent had been engaged in incitement to crime in the present case as follows:
“In the present case the undercover agent only acted in the framework of the offence mentioned in point C of the indictment. [That offence] covered the period from January to June 2009, whereas the judicial investigation had begun on 18 September 2008. On the basis, inter alia, of the regular reports on the undercover work which were submitted during the judicial investigation and the text messages and telephone calls tapped, the agreements and transactions relating to those facts, as well as the prior operations, [were] scrutinised. This information shows that there was no incitement to crime. That is, moreover, confirmed by the fact that other offences of possession, sale, import and export of drugs or psychotropic substances were established in which the undercover agents had played no part.” 30.  On appeal, and following adversarial proceedings, the same court delivered a judgment on 13 October 2011 confirming the first-instance judgment decision in the same terms as before. As he had done before the Court of First Instance, the applicant had requested that the Court of Appeal allow a face-to-face meeting with the undercover agents in order to assess the reliability of their statements. The Court of Appeal dismissed the request with reference to the reasoning of the impugned judgment. It added that it only ascribed relative evidentiary value to the statements of the undercover agents, and that the truth and proof of guilt had also been established on the basis of other evidence. Furthermore, since the applicant had refused to appear at first instance and on appeal, the request for a face-to-face meeting seemed rather academic. 31.  Relying, inter alia, on Article 6 of the Convention the applicant lodged an appeal on points of law with the Court of Cassation against that judgment. As before the Court of Appeal, he alleged that there had been a breach of the right to a fair trial, the rights of the defence and the principle of adversarial proceedings, complaining more specifically of the use by the trial courts of evidence gathered against him even though that evidence transpired from the confidential case file, which had been brought to the attention of the defence neither during the judicial investigation nor during the investigation into the merits of the case. Finally, he criticised the Court of Appeal for dismissing his request for a face-to-face meeting with the undercover agents. 32.  By judgment of 20 March 2012 the Court of Cassation dismissed the appeal on points of law. It dismissed the argument concerning access to the confidential file as follows:
“The fact that, inter alia during the investigation into the merits of the case, the defendant was not allowed to consult the confidential file does not in itself amount to a violation of Article 6 of the [Convention]. Clearly, for the defendant it constitutes a restriction of his defence rights, but that was justified by the need to protect the technical resources used and police investigatory techniques, and to guarantee the safety and anonymity of the persons implementing those techniques.
That restriction of the right to adversarial proceedings is exceptional throughout the proceedings and is counterbalanced by the fact that the lawfulness of the investigative methods implemented is overseen by an independent and impartial tribunal, in this case the Indictments Division, which has discretionary power to ascertain that the content of the criminal file, including the implementation report and the [reports] on the proactive investigation, correspond to the evidence in the confidential file.
Before the trial court, the defendant can also draw on the criminal file to put forward any legal arguments he may wish against the investigative methods used.
Given that the content of the confidential file cannot be used in evidence, there has been no violation of the defendant’s defence rights.
The ground of appeal accordingly has no basis in law.” 33.  As regards the face-to-face meeting with the undercover agents, the Court of Cassation primarily adduced the following:
“Article 6 § 3 (d) of the [Convention] secures the defendant’s right to examine or have examined witnesses against him and to obtain the attendance and examination of witnesses on his behalf; that provision does not prevent the judge from using his unfettered discretion to assess the necessity and relevance of hearing a witness who has been requested and to reject such request, unless that rejection violated the parties’ right to present evidence.
The ground of appeal accordingly has no basis in law.” 34.  For the remainder, the Court of Cassation held that the appellate courts had legally justified their decisions and that in adopting the reasons for the impugned judgment, particularly those concerning the alleged incitement, those courts had replied to the applicant’s specific plea relating to that matter.
...