Privy Council rules on ‘serious irregularity’ challenge in international arbitration Out-Law News | 29 Apr 2021 | 9:24 am | 4 min. read A recent decision by the Judicial Committee of the Privy Council (Privy Council) provides authoritative guidance on what is required in order to uphold a challenge to an arbitral award on the grounds of serious irregularity. In their judgment, Lord Hamblen and Lord Burrows held that a serious irregularity challenge does not require a separate and express allegation of substantial injustice by the applicant and a separate consideration and finding of substantial injustice by the court, in order to be successful. The decision, on a referral by the Court of Appeal of the Commonwealth of the Bahamas, is the first by a highest appellate court to consider the requirement of ‘irregularity causing substantial injustice’ since the 2006 House of Lords judgment in Lesotho Highlands Development Authority v Impregilo SpA. In addition, the judges reviewed a number of significant authorities on challenges to arbitral awards for failures to deal with issues put to the tribunal and failures to give the parties a fair opportunity to present their case.