The Role and Duties of the Expert Witness and Single Joint Experts

This webinar examines the role of the Expert Witness, including the rationale for expert witnesses, the limitations on expert evidence and the distinction between true “expert evidence” and “expert assistance”, as discussed by the Court of Appeal in Rafter v Edmund Rice Schools Trust Co Ltd [2023] IECA 188 and Byrne v Ardenheath Company Ltd [2017] IECA 293 and by the Supreme Court in Hanrahan v Minister for Agriculture [2017] IESC 66.

The webinar analyses the various duties that are owed by an Expert Witness as set out in the seminal UK case of The Ikerian Reefer [1993] 2 Lloyds Rep 68 and refined in the case of Anglo Group plc v Winther Brown & Co Ltd [2000] EWHC Technology 127, which have since been adopted and applied by the Irish courts. These duties are considered in detail under the following headings:

• The duty to tell the truth;
• The duty of independence;
• The duty to ascertain or investigate relevant facts;
• The duty to apply expertise in a professional manner;
• The duty to reach a reasoned and honestly held conclusion;
• The duty to co-operate with the other parties and experts; and
• The duty to comply with directions of the court.

The presentation examines in detail the judgment of the Court of Appeal in Duffy v McGee [2022] IECA 254, where the Court held that the defendant’s expert witness had engaged in a “wholesale abdication” of his duty to the Court and had “impermissibly donned the mantle of a partisan advocate in his efforts to discredit the claim of the plaintiffs”.

The presentation also considers a number of other cases in which the courts have been critical of the expert evidence proffered by one or both parties, including the recent decision of the High Court in Cahill v Seepersad [2023] IEHC 583 where the defendants’ financial advisor was found to have adopted an inappropriate “duality of roles” as both an expert witness and an advocate for the defendants by, among other things, seeking to settle the case on behalf of the defendants and assisting in making a professional complaint regarding the plaintiff’s expert.

Finally, the presentation considers the (still relatively uncommon) practice of appointing single joint experts in Ireland, the legal basis for appointing a single joint expert and the arguments for and against the appointment of a single joint expert.