Alexander Brothers Ltd (Hong Kong SAR) v Alstom Transport SA & Anor

Expert evidence is admissible only where it is reasonably required to resolve the proceedings. The court should consider necessity, assistance and proportionality, including cost, significance and delay. Foreign-law evidence may satisfy this test where it could materially assist a court exercising a statutory discretion.

The defendants sought permission under CPR 35.4 to rely on expert evidence of French criminal law in proceedings concerning enforcement of an international arbitration award. The evidence addressed possible criminal consequences in France if enforcement occurred in England.

The underlying set-aside application relied partly on section 103(3) of the Arbitration Act 1996, which involved a two-stage public-policy inquiry. The issue was whether the proposed evidence was reasonably required under CPR 35.1.

1. Permission granted. The application to adduce the French criminal-law evidence was granted.
2. Under CPR 35.1, expert evidence must be reasonably required to resolve the proceedings. Applying British Airways v Spencer [2015] EWHC 2477 (Ch), the court asks whether evidence is necessary, whether it would assist, and whether it is reasonably required in the proceedings as a whole.
3. The assessment requires a proportionate balancing exercise, including the significance of the proceedings, consequences for the parties, cost, usefulness and delay.
4. Section 103(3) of the Arbitration Act 1996 involves two stages: whether enforcement would offend public policy and, if so, whether enforcement should nevertheless be permitted. The court could not assume that the second stage would be unnecessary.
5. The proposed evidence might assist on the discretionary stage. It was narrow, modest in cost, unlikely to delay the hearing, and potentially significant to the defendants. It was therefore reasonably required. The court did not need finally to determine whether it was also required on the first stage.