Evidence obtained by improper or illegal means: relevance and admissibility in a criminal trial

Abstract

This thesis examines the American and English evidential rules relating to the admissibility of evidence obtained by illegal search or improperly by the police. It attempts to discover the theoretical bases of the different rules in these jurisdictions. The police powers of search are first examined and then the thesis critically discusses the reasons for and the purpose of the English courts' general discretion to exclude relevant evidence; the aim is to determine whether this discretion has the same purpose and function in the various areas of the law of evidence. In my conclusion the real rationale of the American exclusionary rules is the protection of certain fundamental values - the policy and value postulates peculiar to a politically free and democratic society. In using these as focal points the Supreme Court has attributed a dynamic function to the rules of evidence in the area of constitutional law; contrary to the English view the purpose of the evidential rules is not solely to determine the guilt or innocence of the accused. The written constitution, though not the explanation for the strict exclusionary rules, does provide certain important concepts which the Supreme Court has used to justify the bolder approach to supporting the constitutional rights with the rules of evidence. The origin of the American rules is the Court's supervisory jurisdiction over criminal trials. The English rule, on the other hand, is the result of the self-imposed restrictive role of the courts, though there are understandable reasons for this. For England the inclusionary rule may be inevitable, but it has three serious defects. First, it has been arrived at by accident; it lacks theoretical justification and is inconsistent with the confession rule. Secondly, judicial statements as to the Courts' discretion to exclude such evidence are linguistically almost meaningless. Lastly, there appears to be a lack of appreciation that in the area of constitutionally defined rights rules of evidence can have as much importance as substantive rights.