In the absence of an adequate legal basis the evidence collected by the informer may violate Article 8 and the Human Rights Act. I will now look at the impact that the incorporation of Article 6 of the Convention will have in this area. The European Commission and Court have dealt with several cases involving informers, where the applicant has argued that their right to a fair trial has been violated. Essentially Article 6 provides that any one charged with a criminal offence is entitled to a fair and public hearing before an independent tribunal and at minimum has the right to have adequate time and facilities available for the preparation of his defence, and to be able to examine witnesses against him, and to obtain the attendance and examination of witnesses on his behalf under the same conditions as witnesses against him. These cases concern the fairness or otherwise of trials in which anonymous witnesses have been used, and those involving an element of entrapment by under cover police officers.
Parallels exist between anonymous witnesses and the use of screens to hide a witnesses' identity.
They illustrate the obvious dilemma of striking a balance between the protection of witnesses who may be in danger as a result of giving evidence, and the right of any one accused of a crime to have a fair trial, one aspect of which is to confront one's accuser and attempt to impugn their credibility. The Court has not ruled out the use of anonymous witnesses or the use of screens, as long as there are counter balancing measures to enable the reliability of the evidence to be challenged. These measures will vary from case to case, and will depend on whether the accused or his lawyer was present when the witness was questioned, whether they had the chance to ask questions, and whether the trial judge was aware of the witness's identity. Any measures restricting the rights of the defence must be strictly necessary, and the least restrictive method is to be used. A conviction should not be based either solely or to a decisive extent on the evidence of an anonymous witness.