This chapter first discusses the different rules governing public interest immunity and privilege, focusing on the waiver of the right to withhold and the use of secondary evidence if the original is immune from production and inadvertent disclosure. It then turns to public interest in both civil and criminal cases, covering applications to withhold material subject to public interest immunity; ‘affairs of state’ cases; whether the court can question the claim to withhold and by what criteria the claim to withhold should be judged; closed material procedures; the use of methods such as redaction to minimise the effect of a refusal to disclose documents; information given for the detection of crime, etc.; and confidentiality.
18. Public interest immunity and privilege I
Public interest immunity
21. Public policy
The public interest in efficient and fair trials may be seen as underlying the rules of disclosure in civil litigation, whereby a litigant is obliged to make pre-trial disclosure of the documents on which he relies and the documents that adversely affect his own case or adversely affect, or support, another party’s case, even though such documents may not be admissible evidence at the trial. There is also a public interest in enabling material to be withheld where its production would harm the nation or the public service. Where these two kinds of public interest clash and the latter prevails over the former, relevant and otherwise admissible evidence is excluded at trial. Such material is said to be withheld by reason of ‘public interest immunity’. This chapter discusses the development of the modern law on public interest immunity; the scope of exclusion on grounds of public policy; and related procedural issues in civil and criminal cases.