Government Insurance Office of New South Wales v Johnston

The Government Insurance Office of New South Wales (GIO) appealed to the New South Wales Court of Appeal against a decision of the District Court of New South Wales concerning a claim for damages for personal injuries. The respondent, Mr. Johnston, had suffered injuries in a motor vehicle accident and had brought proceedings against GIO as the compulsory third party insurer of the vehicle involved. The core dispute revolved around the assessment of damages, specifically the extent to which Mr. Johnston's pre-existing conditions should be taken into account when calculating his loss.

The primary legal issue before the Court of Appeal was whether the District Court had erred in its assessment of damages by failing to adequately consider the impact of Mr. Johnston's pre-existing degenerative spinal condition on his earning capacity and the extent to which his current injuries had exacerbated that condition. The court was required to determine the appropriate method for apportioning the loss of earning capacity between the injuries sustained in the accident and the pre-existing condition.

The Court of Appeal, in its reasoning, affirmed the principle that where a plaintiff suffers from a pre-existing condition, the defendant is only liable for the aggravation or exacerbation of that condition caused by the defendant's negligence. The court held that the District Court had made an error in its approach to assessing the loss of earning capacity, as it had not sufficiently distinguished between the loss attributable to the accident and the loss that would have occurred in any event due to the pre-existing condition. The court applied the principles established in cases concerning the assessment of damages for pre-existing conditions, emphasizing the need to isolate the impact of the tortious act.

The Court of Appeal allowed the appeal, setting aside the District Court's judgment and remitting the matter back to the District Court for a re-assessment of damages in accordance with the principles articulated by the Court of Appeal.