Experts and legal professional privilege

Key Points:

Assume all communications between legal advisers and experts have the potential to be disclosed to the opposing party.

We've previously outlined what expert evidence is, who is an expert and the procedural requirements to be observed when engaging an expert. In this article, we look at what communications and materials will be protected by legal professional privilege under NSW law and how legal advisers should conduct themselves when working with experts.

What is legal professional privilege?

Legal professional privilege is a right to maintain confidences between parties. When a document is protected by privilege, it means that it does not need to be disclosed.

In the context of litigation and retaining expert witnesses, privilege will apply to confidential oral or written communications between the client and his or her legal advisers and the expert for the dominant purpose of obtaining or receiving advice for the purpose of existing or anticipated legal proceedings.

"Dominant" in this context means the ruling or prevailing purpose. The purpose or intended use for which a document is brought into existence will be a question of fact.

How is privilege waived?

Legal professional privilege may be waived or lost where there is conduct inconsistent with the maintenance of the privilege. Examples include not keeping the advice confidential, partially disclosing a privileged communication or using it to explain why a certain action was taken or not taken.

The general principle is that if it would be unfair for the person to maintain the privilege after a disclosure, then there may be a waiver of privilege (Attorney General for the Northern Territory v Maurice (1986) 161 CLR 475; Goldberg v Ng (1995) 185 CLR 83; Mann v Carnell (1999) 201 CLR 1). Waiver of privilege with respect to expert witnesses will arise because the expert evidence on which a party proposes to rely must be filed and served before the trial.

Expert witnesses

When expert witnesses are retained to prepare a report to be filed and served in proceedings, the production of the final report will be based upon numerous documents including instructions, source materials, drafts, working documents and confidential communications with legal advisers.

In terms of privilege and expert witnesses, two types of documents are to be distinguished:

communications between the expert and the legal advisers/client; and associated documents including drafts, memoranda and notes produced...