Analysis of Município De Mariana & Ors v BHP Group (UK) Limited: Balancing Amendments in Civil Procedure

Citation: [2024] EWHC 23 (TCC)
Judgment on


The case of Município De Mariana & Ors v BHP Group (UK) Limited offers notable insights into legal principles regarding amendment applications, the impact of foreign law in English court proceedings, understanding limitation defences, and the balance courts strike to comply with the overriding objective. The case stems from the tragic collapse of the Fundão Dam in Brazil, for which the claimants sought damages against the defendant, BHP Group, under Brazilian law. This analysis will focus on the recent judgment of Mrs Justice O’Farrell, particularly the court’s discretion in allowing amendments to claimants’ pleadings at various stages of litigation.

Key Facts

The claimants sought to amend allegations concerning the defendant’s knowledge and involvement in the dam’s operation, introduce new heads of loss, and revise their responses to the defendant’s limitation defence and settlement agreements. These proposed amendments elicited objections from the defendants, stressing the impact on the pre-set trial timetable and ongoing preparation burdens. Mrs Justice O’Farrell reviewed these applications under the relevant provisions of the Civil Procedure Rules (CPR), especially in light of the impending trial date.

The court employed several pertinent legal principles:

  1. CPR 17.1 and CPR 17.3: These rules govern the amendment of statements of case after they have been served. They allow for amendments with either the consent of all parties or with permission from the court.

  2. Late Amendments: Any amendment sought after the trial date has been fixed is considered late, intently scrutinized, and necessitates a strong justification from the party seeking the amendment. The court underlined the principle from CIP Properties (AIPT) Ltd v Galliford Try Infrastructure Ltd [2015] EWHC 1345 (TCC) and Quah Su-Ling v Goldman Sachs International [2015] EWHC 759 concerning late amendments and the compulsory balancing act between justice for the applicant, the counterparty, and the wider administration of justice.

  3. Overriding Objective: Under CPR 1, the court’s overriding objective to deal with cases justly and at proportionate cost includes ensuring the expediency and fairness of proceedings, economizing expense, and judiciously managing court resources.

  4. Amendment Test: The amendments sought must be presented as arguable, coherent, and properly particularised. The court emphasized that an amendment can be rejected if it clearly lacks prospects for success.

  5. Burden of Justification: The onus is on the party seeking an amendment to demonstrate the significance and feasibility of the amended case and its impingement on the trial timetable.


The court granted permission for some amendments whilst refusing others, segmenting the proposed changes into four categories; updates to Brazilian law, amendments to the factual case alleged, heads of loss, and points in the reply concerning limitations and settlements. The court took particular note of whether the amendments would unduly burden the preparation for the upcoming trial and whether refusing amendments would cause injustice to the claimants. Notable outcomes include:

  • Brazilian Law Amendments: Permission granted, no significant additional burden on the defendants, and serious prejudice risk to the claimants if disallowed.
  • Amendments to the Factual Case: Refused for paragraph 196A due to inadequate particularisation. Granted for paragraph 205A, which sets out a clear, arguable case.
  • Heads of Loss Amendments: Granted, to be addressed post the first-stage trial due to timing.
  • Amendments to the Reply: Granted, issues already included in the trial, and amendments not burdensome.

The claimants were instructed to bear the costs for the amendments and were given a segment of the application costs because while they partly succeeded, they were also partly unsuccessful.


Mrs Justice O’Farrell’s decision illustrates the careful balance courts maintain in amending pleadings, considering the dual imperatives of ensuring fair presentation of arguments and adhering to a proportionate, expeditious legal process. The judgment reflects a meticulous approach to assessing the cogency and preparation state of both parties and upholding the integrity of the trial timetable. It demonstrates the importance of precise pleading to allow the opposing party to grasp the case adequately, signifying a continued endorsement of clarity and judicial economy as cornerstones of UK civil procedure.

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