On 6 May 2026, the Court of Appeal refused BHP's application for permission to appeal against the High Court’s findings that it is liable for the collapse of the Fundão dam in Brazil.

Background

In November 2025, Mrs Justice O'Farrell found BHP liable for the collapse of the Fundão dam; liability was established not as a matter of English law but under Brazilian environmental law and the Brazilian Civil Code (the "Liability Judgment"). O'Farrell J also held (amongst other things) that the claims were not time-barred by prescription (i.e. limitation). More information on the judgment is in a previous blog post here.

Following a post-judgment consequentials hearing in January 2026, O'Farrell J refused permission to appeal on all grounds other than costs.

In February 2026, BHP applied to the Court of Appeal for permission to appeal the Liability Judgment and for expedition of the appeal if permission were granted. BHP sought and was granted an expedited oral hearing for its applications, which were heard by Lord Justice Lewison and Lord Justice Fraser on 12 March 2026.

What were the key issues for the Court of Appeal to decide?

BHP advanced five grounds of appeal, grouped into three categories:

• Ground 1 related to the finding that BHP was strictly liable as a “polluter” under Brazilian environmental law;
• Ground 2 related to fault‑based liability under the Brazilian Civil Code; and
• Grounds 3, 4 and 5 concerned limitation under Brazilian law.

BHP sought permission to appeal not only on the basis that the decision was wrong (i.e. under CPR 52.21(3)(a)), but also that the decision was unjust because of serious procedural irregularity (under CPR 52.21(3)(b)); specifically, BHP submitted that the procedural irregularity was an alleged failure by O'Farrell J to engage with its case.

The Liability Judgment was decided almost exclusively by reference to Brazilian law. As a matter of English law, questions of foreign law are treated as questions of fact. BHP therefore faced the high threshold applicable to appeals against findings of fact: it had to show that the Judge’s conclusions were "plainly wrong", meaning that her findings must be unsupported by evidence or otherwise irrational.

Before turning to the relevant grounds of appeal, Fraser LJ (with whom Lewison LJ agreed) provided a detailed overview of the principles relevant to appellate decision-making. He emphasised the strict guidance from Volpi v Volpi [2022] EWCA Civ 464 regarding appeals of fact:

"an appeal court is bound, unless there is compelling reason to the contrary, to assume that the trial judge has taken the whole of the evidence into his consideration. The mere fact that a judge does not mention a specific piece of evidence does not mean that he overlooked it."

Fraser LJ referred to this throughout his judgment and suggested that BHP, while recognising the high bar for any appeal, had sought to avoid that bar by focusing upon what was said to be a failure by the trial Judge to engage with its case.

The Court of Appeal's decision and key reasoning

Ultimately, Fraser LJ held that BHP was "a world away" from surmounting the high threshold for each of its five grounds of appeal. He rejected the suggestion that O'Farrell J's conclusions were ones which no reasonable Judge could have reached. There were no free-standing errors of principle and no serious procedural irregularities. The trial Judge had applied her findings on Brazilian law to facts established after a lengthy trial involving extensive expert evidence. Her conclusions were rationally open to her.

In rejecting BHP's submission that O'Farrell J had failed to engage with its case, Fraser LJ stated that BHP’s attempt to isolate individual documents for appellate scrutiny was “island-hopping”, which would not lead to a balanced picture of the whole ocean of factual evidence. BHP was wrong in law to assume that because the trial Judge did not mention a specific piece of evidence or line of argument in her Liability Judgment, she had overlooked them.

Further detail on Fraser LJ's reasoning regarding each of the five grounds of appeal is set out below.

Ground 1: Strict Liability

The Court of Appeal held that it was not reasonably arguable that the trial Judge had been wrong to hold that BHP were strictly liable as "polluters" under applicable Brazilian law: her findings were supported by evidence; they were not irrational; and they were not contrary to expert evidence. There was no basis for any claim that O'Farrell J had failed to engage with BHP's case.

BHP’s alternative submission, that she had made “critical errors” in applying a multifactorial test, particularly concerning BHP’s degree of control over its 50% subsidiary Samarco, was also rejected. Fraser LJ found that the trial Judge's conclusions were not challengeable on appeal: she had reached her conclusions on "the whole ocean of factual material" before her, arriving at a conclusion that was properly open to her and not irrational. BHP's arguments were, in substance, challenges to factual findings dressed up as procedural irregularities.

Ground 2: Fault-Based Liability

BHP argued that the trial Judge failed to engage with its case on fault-based liability. However, the Court of Appeal found this difficult to square with her "careful and detailed analysis", which on some issues had actually preferred BHP's case and BHP's expert evidence.

BHP also argued that aspects of the claimants’ case on audit and risk management were not pleaded. However, Fraser LJ found that this "was not a valid submission": there was no compelling reason to doubt that O'Farrell J took all the evidence and arguments before her into consideration.

Grounds 3, 4, and 5: Limitation

BHP's claims that the trial Judge failed to engage on the three areas of Brazilian limitation law were described as "groundless". These had been included in the agreed list of issues for trial and dealt with in the Liability Judgment.

Implications

Fraser LJ described the litigation as “the very definition of a heavy case” and noted the significant public interest in the Court of Appeal's reasons.

The judgment serves as a reminder of the high bar facing appellants seeking to challenge findings of fact. That threshold is particularly difficult to overcome where those findings are based on extensive expert evidence following a long trial. Only in the rarest of cases will an appellate court be convinced that the trial Judge was wrong and so interfere with their findings of fact. Part of the reason for this approach is, as expressed in FAGE UK Ltd v Chobani, that “the trial judge will have regard to the whole sea of evidence presented to him, whereas an appellate court will only be island‑hopping”.

The upshot of all of this would appear to be that in cases which are determined almost exclusively on the basis of foreign law, parties which are unsuccessful at first instance may find that the appellate courts are effectively not available to them. Indeed, for as long as the English Courts treat matters of foreign law as questions of fact and the Court of Appeal maintains a high bar for interfering in findings of fact, the practical reality in many/most such cases would be that the avenue for appealing a first instance judgment is narrower even than the grounds for appealing or setting aside an arbitral award. This may be the law of unintended consequences at work, but if the English Courts are going to continue to take on exclusively foreign law-governed cases, then some accommodation may be required, to give parties to those cases the same access to the appellate Courts as other litigants.