ABSTRACT
This chapter deals with the reasons for excluding evidence that relate to it being either privileged or having some immunity from inclusion relating to the public interest. The reason for the existence of other exclusionary rules or principles is the need to secure a fair trial. Relevant evidence can be excluded because it is likely to mislead the jury1 or because it would have an adverse effect on the fairness of the proceedings.2 The justifi cation for the rules relating to privilege and public interest immunity has nothing to do with the fairness of the trial but with some outside issue which is thought to be more important. The rules concerning privilege and public interest immunity acknowledge that the public have an interest that may occasionally be allowed to prevail over the interest in securing a fair trial at which all relevant and otherwise admissible evidence can be heard. A privilege is a right which the law gives to a person allowing him to refuse to testify on a particular matter or to withhold a document from the proceedings. Public interest immunity (PII) arises where the courts have the power to exclude evidence from the general duty of
disclosure on the grounds that disclosure of the information in question would be damaging to society as a whole.
