The English High Court has authorised public access to unredacted pleadings concerning the parameters and values used by OEMs to regulate vehicle emissions control systems, following a judgment by Mr. Justice Constable. He concluded there was "no proper justification" for retaining the redactions.
In October, the Court will hear arguments on the liability of five OEMs, Ford, Mercedes-Benz, Nissan, Peugeot-Citroen, and Renault (the "Lead Defendants"), in the ongoing Pan-NOx emissions group litigation, arising from the Dieselgate scandal (the "Liability Trial"). The group actions involve allegations that these manufacturers employed prohibited defeat devices ("PDDs") in their vehicles and are brought on behalf of a cohort of over one million claimants.
A key issue before the Court was the extent to which information over which the Lead Defendants asserted confidentiality should be de-designated and made accessible, which would necessitate removing redactions from pleadings for the upcoming Liability Trial.
This issue was resolved with Mr. Justice Constable's decision in Various Claimants v Mercedes-Benz Group AG & Others [2025] EWHC 1931 (KB), which resulted in the prior confidentiality measures being removed.
Background
The core technologies and strategies at the centre of the group actions have long been subject to confidentiality disputes. OEMs argued that proprietary technical information should not be disclosed to other defendants or made available to the public, on the basis that such information could be used to their commercial disadvantage. To this end, confidentiality ring orders ("CROs") were implemented among individual claimant and defendant groups (and among the Claimants and Lead Defendants) to restrict access to sensitive documents, many of which were placed within the CROs on a precautionary basis due to the compressed timeline of the case and the disclosure burden on OEMs.
The Claimants, supported by non-parties interested in the group actions, including ClientEarth, Mums for Lungs, and the Scottish NOx Emissions Steering Group (the "Interested Parties"), sought to have relevant redactions removed from the pleadings. They argued that this was essential to understanding the issues in the proceedings, including how the PDDs operated.
The Traffic Light Proposal
In efforts to balance confidentiality concerns, the Lead Defendants proposed a classification system under which documents would be placed in one of three categories:
- Green: Non-confidential documents that could be read in open court.
- Amber: Documents that were to be treated as 'confidential in principle' for the purposes of the Liability Trial, that could be read in court reading but with restrictions attached to their reporting and collateral use.
- Red: Highly confidential documents that could not be read out in court, with restrictions on both reporting and collateral use.
During the hearing, the proposal was revised to remove reporting restrictions altogether, effectively meaning there was no distinction between how a green or amber document would be treated in terms of reporting. However, disagreements persisted over the classification of certain documents and most notably, the parameters and values for vehicle emission system modulation, where the majority of Lead Defendants supported an "amber" designation, but Mercedes argued they should be classified as "red."
All the Lead Defendants were however in agreement that, even if it read out in court, such information should stay redacted in the pleadings.
Decision
The Lead Defendants contended that disclosing such technical details would expose them to commercial harm, arguing that design principles and development data remain valuable long-term. Mr. Justice Constable rejected these assertions, noting in particular the absence of evidence that the parameters in dispute could be relevant to newer vehicle designs required to conform with Euro 6d or Euro 7 standards. He also agreed with the Claimants that the firmware for many vehicles was publicly available online, so that the risk of damage to the Lead Defendants from disclosure was one that was more perceived than real.
Most significantly, Mr. Justice Constable held that even if the values and parameters were highly commercially sensitive, the public interest weighted in favour of allowing the pleadings to be available to the public in unredacted form. This was particularly so given that the serious allegations of misconduct against the Lead Defendants were, prima facie, credible. He found that, just as it had been accepted by the Lead Defendants that the figures should be designated as amber (in order to allow the public to 'follow along' in court), without access to the parameters and values in the pleadings, members of the public who did not attend the Liability Trial would have no way of understanding the issues between the parties.
Consequently, Mr. Justice Constable ordered the pleadings to be made available in unredacted form immediately.
Implications
This case exemplifies the principle of open justice within the English legal system, particularly in matters of significant public interest. Mr. Justice Constable's decision underscores that even highly commercially sensitive information can be made public when proceedings involve credible allegations of serious misconduct, since public confidence in the legal system and understanding of the issues in dispute are paramount.
A formal judgment on whether the allegations of misconduct are substantiated will come with the conclusion of the upcoming Liability Trial.
Disclaimer: This Alert has been prepared and published for informational purposes only and is not offered, nor should be construed, as legal advice. For more information, please see the firm's full disclaimer.
