Permission to appeal refused in landmark Brazilian dam litigation

Municipio de Mariana v BHP Group (UK) Ltd and BHP Group Limited [2026] EWCA Civ 502

On 6 May 2026, the Court of Appeal handed down its judgment in the latest instalment of the litigation arising out of the collapse of the Fundão Dam in Brazil, brought by over 600,000 claimants against BHP. Fraser LJ described the case as the “very definition of a heavy case” and “somewhat notable in scale”, even by the standards of the TCC. On 14 November 2025, O’Farrell J ruled that BHP was strictly liable for the Collapse under the Brazilian Environmental Law, and was at fault for the Collapse under the Brazilian Civil Code: see [2025] EWHC 3001 (TCC). In February 2026, BHP applied for permission to appeal. Following an oral hearing before Lewison and Fraser LJJ, the Court has dismissed BHP’s application.

BHP sought permission to appeal on five grounds, which were said to give rise to up to 14 points. Grounds 1 and 2 concerned BHP’s strict and fault-based liability, whilst grounds 3-5 concerned limitation. The crux of BHP’s complaint on each ground was that O’Farrell J’s judgment was tainted by serious procedural irregularity due to a failure to properly engage with BHP’s submissions.

In a judgment running to 34 pages and 147 paragraphs, the Court of Appeal found that none of BHP’s proposed grounds for appeal had a real prospect of success and there was no other compelling reason for granting permission to appeal. The Court of Appeal emphasised the limited scope for an appeal court to interfere with findings of foreign law pursuant to the decision in Perry v Lopag [2023] UKPC; the proper approach of the Court of Appeal to appeals on fact as set out in FAGE UK Ltd v Chobani [2014] EWCA Civ 5; and appeals involving findings based on expert evidence, as in Volpi v Volpi [2022] EWCA Civ 464. The Court found that BHP had failed to adhere to many of the principles established by these authorities and did not “come close” to meeting the standard necessary to challenge O’Farrell J’s findings.

A Stage 2 Trial has been set down to commence in April 2027 to determine quantum of the claims by reference to 40 lead claimants.

Jonathan McDonagh acted for the successful Claimants before the Court of Appeal. He was instructed by Pogust Goodhead alongside Alain Choo Choy KC and Andrew Fulton KC.  Jonathan, with Sophie Holcombe, Ryan Tang, Suzanne Ter-Minassian, Henry Fahrenkamp and Shaun Matos act for the Claimants in Stage 2 of the proceedings.