Permission to appeal in heavy TCC litigation: “failure to engage” does not dilute appellate restraint on findings of fact and foreign law
Key holdings (what this decision adds)
- “Failure to engage” is not a shortcut: a complaint framed as “the judge failed to engage with our case” will usually amount to a disguised challenge to findings of fact, weight, and evaluation; it does not lower the Fage/Volpi appellate threshold.
- No “textual audit” of a heavyweight judgment: appellate review should not proceed by minute textual analysis or by inferring oversight from silence; absent a compelling reason, the appellate court assumes the trial judge took the whole evidential “sea” into account.
- Foreign law findings intensify restraint: where foreign law (here, Brazilian civil law) is proved by expert evidence and treated as fact, the appellate court is materially disadvantaged and should be slow to interfere.
- Transcript-only re-trial is exceptional to the point of being unrealistic: where a retrial would be required, the court emphasised the importance of live oral evidence and cautioned against suggestions that reading transcripts can replicate trial evaluation.
- Expedition can be appropriate for a self-contained costs point even where substantive permission is refused, given the scale of costs and the value of early certainty.
1. Introduction
This decision concerns attempts by the corporate defendants (“BHP”) to obtain permission to appeal against a substantial Technology and Construction Court (“TCC”) Stage 1
liability judgment ([2025] EWHC 3001 (TCC)) arising from the collapse of the Fundão Dam in Brazil on 5 November 2015.
The claimants (over 600,000 Brazilian parties including individuals, municipalities, utilities, institutions and businesses) sue BHP in England, with Brazilian law governing
key liability and limitation issues.
The proposed appeal was framed not only as alleging error, but as asserting that “something has clearly gone wrong in the judicial process” because the trial judge supposedly
“failed to engage” with BHP’s case (invoking CPR 52.21(3)(b): “unjust because of a serious procedural or other irregularity”).
The Court of Appeal treated that framing as central: it required the court to police the boundary between (i) true procedural unfairness and (ii) dissatisfied re-argument of facts,
expert evaluation, and foreign-law findings.
The court also dealt with expedition. Permission had already been granted below on a single costs-interest ground (in [2026] EWHC 73 (TCC)), and the Court of Appeal
had to decide whether to expedite any appeal.
2. Summary of the judgment
2.1 Permission to appeal
- Permission refused on all substantive grounds challenging Stage 1 liability and limitation findings (Grounds 1–5).
- The court held there was no reasonably arguable error of law/fact, no rationality flaw, and no serious procedural irregularity based on “failure to engage”.
- The court repeatedly characterised BHP’s approach as impermissible “island-hopping” through selected documents and transcript snippets to re-run a case decided after a very long trial.
2.2 Expedition
- Expedition granted only for the surviving costs-interest appeal point (interest on pre-judgment costs linked to funding/success fee), with the court indicating an October listing might be possible.
- Because substantive permission was refused, expedition to avoid potentially redundant Stage 2 preparation was “otiose”.
3. Analysis
3.1 Precedents cited and how they shaped the outcome
(A) Appeals on fact and evaluation: the high bar
The decision is anchored in a line of authority restricting appellate interference with findings of fact, evaluation, and inferences:
- FAGE UK Ltd v Chobani [2014] EWCA Civ 5 (Lewison LJ): appellate courts should not interfere with factual findings unless compelled; the trial judge sees the “whole sea of evidence” while the appellate court is “island hopping”; and there is no duty to deal with every argument.
- McGraddie v McGraddie [2013] UKSC 58: “plainly wrong” is a stringent standard; appellate intrusion is rare.
- Thomson v Kvaerner Govan Ltd [2003] UKHL 45 (quoted): only “the rarest occasions” justify disturbing the trial judge’s formed opinion.
- Thomson v Christie Manson and Woods Ltd [2005] EWCA Civ 555: warning against “cherry picking” points to dismantle an interlocking “jig-saw” of expert evidence.
- Volpi v Volpi [2022] EWCA Civ 464: reinforced that
(i) “plainly wrong” means no reasonable judge could reach the decision,
(ii) silence about a specific item is not oversight, and
(iii) judgments should not be subjected to narrow textual analysis.
These authorities did the decisive work: the court treated BHP’s “failure to engage” case as relying on exactly what Volpi forbids—
inferring disregard from omission and picking over a massive judgment as if it were “legislation or a contract”.
(B) Expert evidence and specialist courts (TCC)
- Byers v Saudi National Bank [2022] EWCA Civ 43: caution in appeals against evaluation of expert evidence.
- Griffiths v TUI (UK) Ltd [2021] EWCA Civ 1442: even uncontroverted expert evidence need not be accepted.
- Kingley Developments Ltd v Brudenell [2016] EWCA Civ 980: judge may prefer non-expert evidence over expert opinion in appropriate contexts.
- Wheeldon Brothers Waste Ltd v Millenium Insurance Co Ltd [2018] EWCA Civ 2403: summarised that permission to appeal on TCC fact/expert evaluations faces an especially high hurdle (references in the judgment include Virgin Management, Skanska, Grizzly Business, and Yorkshire Water as part of that line).
Fraser LJ used these to emphasise the institutional point: in specialist, technically dense TCC litigation, appellate “unpicking” is particularly unattractive,
and permission to appeal is a genuine filter rather than a step towards a rehearing.
(C) Unfair trials and the remedy
BHP’s case implied the trial was unjust due to irregularity. Fraser LJ invoked:
- Serafin v Malkiewicz [2020] UKSC 23: where a trial is unfair, the judgment is “written in water” and the logical consequence is a complete retrial.
This was used to highlight the seriousness of alleging “irregularity”: if such a claim were made out, the remedy is drastic. The court treated BHP’s position as internally strained:
BHP argued for “irregularity” yet suggested a retrial could proceed without oral evidence, simply by reading transcripts—an approach Fraser LJ described as “extraordinary”.
(D) Foreign law as fact; appellate disadvantage
- Perry v Lopag [2023] UKPC 16: emphasised that where a judge chooses between disagreeing foreign-law experts, the evaluation depends on how experts reason and answer under cross-examination—matters not fully captured by a judgment or transcript.
- Banca Intesa Sanpaolo and another v Comune di Venezia [2023] EWCA Civ 1482: cited as part of the modern approach to foreign-law issues.
The court rejected BHP’s submission that there is “greater scope” to interfere with a trial judge’s application of foreign law to facts. In this case (Brazilian civil law, Portuguese language, STJ jurisprudence),
the appellate court’s disadvantage was said to be “significant”, reinforcing restraint.
(E) Judgment reasons: adequacy not perfection
These authorities underpinned the court’s rejection of the idea that the length of the reasons on a point (notably limitation) evidences “how badly things have gone wrong”.
3.2 Legal reasoning (why permission was refused)
(A) The court’s diagnosis: “failure to engage” as a re-labelling exercise
Fraser LJ treated BHP’s applications as repeatedly doing two impermissible things:
- Minute textual analysis of a 1,129-paragraph judgment to identify alleged omissions; and
- Reversed inference: assuming that if an argument or document is not expressly mentioned, the judge overlooked it (contrary to Volpi).
On this footing, the “serious procedural irregularity” claim largely collapsed: the court found that the asserted irregularity was not independent of the merits; it was a complaint about weight and outcome.
(B) Ground 1 (Brazilian Environmental Law strict liability as “polluter”)
BHP argued the trial judge applied the wrong test (direct polluter = operator; indirect polluter only where a safety duty exists) and that the “correct test” was said to be agreed by experts.
The Court of Appeal:
- Held the judgment accurately summarised BHP’s case and addressed it over an extended section.
- Rejected the asserted “concession”/agreement by the claimants’ expert: the alleged agreement did not appear in formal expert agreement; transcript snippets were said to be taken out of context; and the trial judge had already considered and rejected the “concession” argument.
- Characterised BHP’s documentary reliance as “island-hopping”, not establishing irrationality or oversight.
On the alternative “critical flaws” attack (control; use of shareholder powers; causation), the court treated (a) and (b) as classic factual challenges, and (c) as contradicted by the trial judge’s detailed causation analysis,
including extensive review of Brazilian STJ decisions (the court specifically rejected the submission that there was no analysis of the “underlying case-law”).
(C) Ground 2 (fault-based liability under Article 186 of the Brazilian Civil Code)
Although alternative to strict liability, the Court of Appeal still dealt with the permission request in outline.
It pointed to the trial judge’s structured treatment of:
- Disputed Brazilian law expert issues on omission-based fault and causation (Article 403 framework);
- Attribution of conduct to BHP rather than Samarco; and
- Corporate law expert disagreements (including that the trial judge preferred BHP’s corporate-law expert on some issues), undermining the narrative of a one-sided “non-engagement”.
The court again treated the “procedural irregularity” claim as an attempt to relitigate fact and evaluation.
(D) Pleading objections in heavy commercial litigation: list of issues, prejudice, and practicality
On objections that certain audit and risk-management allegations were not pleaded, Fraser LJ emphasised TCC practice:
the agreed list of issues is pivotal in complex trials and, by trial, pleadings are “foundation documents” often overtaken by served evidence and crystallised issues.
He also noted the absence of identified prejudice and cited the trial judge’s own conclusion that the material allegations were pleaded, albeit via a “tortuous” path.
The important analytical point is the court’s reluctance to let late pleading technicalities—raised after evidence has been tested—drive appellate intervention absent concrete unfairness.
(E) Limitation (Grounds 3–5): foreign-law findings and brevity of reasons
BHP challenged findings that (i) limitation was suspended (Article 200), (ii) a five-year period applied (Article 27 of the Consumer Defence Code), and (iii) municipalities/public entities were subject to the 1932 Decree.
The court refused permission, holding:
- There was no “failure to engage”: the judgment identified and decided the issues, and in at least one ground expressly summarised BHP’s position before preferring opposing expert evidence.
- The shortness of a reasoning passage is not itself a marker of irregularity, particularly in a very large judgment.
- Broader “importance” arguments (e.g., alleged reliance in Brazilian appeals) did not provide a “compelling reason” for permission: the TCC cannot bind Brazilian courts on Brazilian law.
3.3 Impact (practical consequences)
- Appellate gatekeeping in mega-litigation: the decision underscores that permission to appeal is not a staging post for re-argument in technically and legally dense cases with extensive expert evidence and foreign law.
- “Failure to engage” claims will be scrutinised: parties should expect the Court of Appeal to test whether such claims truly allege procedural unfairness, rather than dissatisfaction with evidential weight or adverse findings.
- Foreign-law cases: where foreign law is heavily contested by experts (especially in non-common-law systems), the trial judge’s assessment of expert reasoning and oral answers is given heightened respect.
- Case management and pleadings: the emphasis on lists of issues and prejudice signals a modern, pragmatic approach—particularly relevant to group claims and mass torts where pleadings inevitably evolve.
- Costs/funding issues: expedition granted on the costs-interest point highlights the court’s willingness to prioritise self-contained issues with large financial consequences, even while substantive challenges are filtered out.
4. Complex concepts simplified
4.1 “Foreign law is treated as fact”
English courts generally require parties to prove foreign law by expert evidence. The English judge then makes findings—treated procedurally as findings of fact—about what the foreign law is and how it applies.
On appeal, the same deference applies as to other factual findings, especially where the trial judge chose between competing experts.
4.2 “Plainly wrong” and why silence is not oversight
“Plainly wrong” does not mean the appeal court would have decided differently. It means the decision is outside the range a reasonable judge could reach.
And a judge’s failure to mention a point does not show it was ignored; appellate courts presume the trial judge considered the whole body of material unless there is a compelling reason to think otherwise.
4.3 “Serious procedural irregularity” (CPR 52.21(3)(b))
This is about the fairness and integrity of the process (e.g., being deprived of a fair opportunity to present a case), not about losing on the merits.
The Court of Appeal treated BHP’s “failure to engage” label as, in substance, an attempt to re-open factual and evaluative issues.
4.4 Why a transcript-only “retrial” is problematic
The evaluation of oral evidence includes demeanour, responsiveness, and how answers withstand cross-examination—elements a transcript cannot fully capture.
Where a retrial is required, the court suggested that a proper rehearing with oral evidence is ordinarily necessary, particularly in expert-heavy cases.
5. Conclusion
Municipio de Mariana v BHP [2026] EWCA Civ 502 is primarily a decision about appellate discipline in exceptional, resource-intensive litigation involving foreign law and extensive expert evidence.
The Court of Appeal refused permission across all substantive liability and limitation grounds, holding that allegations of “failure to engage” did not disclose any serious procedural irregularity and largely amounted to impermissible attempts to re-argue fact and expert evaluation.
The court nevertheless expedited the remaining, discrete costs-interest appeal point, recognising the case-management value of early certainty given the scale of costs.