      offence etc. It may also prevent the defence from carrying out or proposing investigative actions to obtain exculpatory evidence. Whilst Article 6(3) requires the provision of detailed information on the accusation and the nature and legal classification of the offence ‘at the latest’ upon submission of the merits of the accusation to the judgment of a court, this is simply recognising the fact that full information will always have to be provided then in order for a trial to take place. Preserving the fairness of the proceedings and ensuring effective exercise of the rights of defence at trial may require fuller information earlier on. Indeed, Article 6(4) requires that suspects and accused persons are notified ‘promptly’ of any changes in the accusation where this is necessary to safeguard the fairness of the proceedings. This recognises the fact that changes to the accusation may affect the conduct of the defence, and that withholding such information may prejudice that fairness. Despite requests made earlier in the proceedings for fuller information, which it would have been possible to provide, this was not provided and the Directive was therefore breached. This caused prejudice to the suspect, e.g. s/he gave statements which were held against him/her subsequently. The fact that this may have been consistent with national law is not determinative. The court must ensure the effectiveness of the Directive and take action if the standards of the Directive are not respected. Accordingly, the court must take action to remedy the failure of the Directive (disregarding the evidence, invalidity of the act etc.). If the court is in doubt as to the meaning of the provisions, it should make a reference for a preliminary ruling to the CJEU. 31