On 7 August 2026, the High Court handed down its costs judgment in Abbott & Others v Ministry of Defence, the landmark military Noise-Induced Hearing Loss (NIHL) litigation in which the Court determined a series of generic issues affecting tens of thousands of claims brought by former members of the Armed Forces. The judgment was delivered by Mr Justice Garnham, sitting with Master Brown as assessor.
The claimants sought an order requiring the MOD to pay 95% (initially 100%) of their common costs, while the MOD contended that the overall outcome was genuinely mixed and that no order as to costs should be made. The Court ultimately ordered the MOD to pay 60% of the claimants’ common costs, a significantly lower figure than that sought by the claimants.
More importantly, the judgment provides detailed judicial commentary on which party succeeded on each generic issue and the likely impact of those findings across the wider cohort of military hearing loss claims. The judgment provides further valuable guidance on the practical significance of the substantive decision handed down in April 2026.
As per CPR 44.2 the Court has a very wide discretion as to costs. However, the general rule is that an “unsuccessful party will be ordered to pay the costs of the successful party”. However, “the court will have regard to all the circumstances, including… whether a party has succeeded on part of its case, even if that party has not been wholly successful”.
The claimants’ arguments focused on the Court of Appeal guidance in Fox v Foundation Piling [2011] EWCA Civ 790 that, in a personal injury context, partial success is not normally a reason for depriving a successful party of its costs.
The defendant however drew attention to the fact that while not technically a GLO, there were parallels in the way these matters were conducted and consideration should be given to CPR 46.6 and Kupeli v Atlasjet [2018] 3 Costs LR 555, where the Court of Appeal looked into this. Reference was given to para 61, which noted that a group claim is run so that, as well being a “vehicle of preliminary issues and/or lead claims”, it is intended to guide future claims and that “the direction any money travels as a result of a group claim trial may not always properly reflect ‘success’”.
The Court emphasised that this was not an ordinary personal injury claim between individual parties. Instead, it was a form of test case litigation intended to determine issues affecting a substantial cohort of military NIHL claims. As a result, success could not simply be measured by who recovered damages in the individual lead cases. The Court was required to consider both the outcome of each generic issue and its consequences for the wider cohort as a whole.
Having undertaken that exercise, the Court concluded that the claimants achieved important successes on several key scientific and quantification issues. However, the Court also expressly recognised that the MOD secured significant victories on military audiology evidence, latency and acceleration, cochlear synaptopathy, and future loss of earnings.
Importantly, the costs judgment does not alter the substantive findings reached in April 2026. The costs judgment represents the Court’s assessment of the relative significance of those findings and their impact across the wider cohort, rather than any reconsideration of the underlying scientific issues. It does, however, offer some certainty in respect of those issues – providing a clear understanding and intention of the Court’s findings in the substantive judgment.
The Court found that the claimants were successful on a number of the central scientific issues:
· Diagnostic Methodology
The Court accepted the claimants’ preferred rM-NIHL diagnostic methodology and rejected the defendant’s preferred CLB approach for military cases. The Court described the claimants as substantially successful on this issue. It also made clear that the original M-NIHL method, and the MLP(18) AI method, were unsuitable for use in claims.
· Foundational Concepts
The Court preferred the more recent ISO 7029:2017/2024 standard, accepted the need for a baseline correction (of 2.4dB) to the underlying AAHL data set, and rejected an automatic deduction at 6kHz for TDH39P earphone testing. Importantly, this was for both diagnosis and quantification.
· Quantification Methodology
The Court preferred the Moore, Lowe and Cox (MLC) approach to quantification advanced by the claimants, albeit with important qualifications advanced by the MOD regarding percentile selection, use of conventional hearing thresholds, and application of the 4:1 binaural calculation. The Court regarded the claimants as substantially successful overall on quantification.
Although the claimants recovered a proportion of their costs, the costs judgment strongly reinforces a number of successes for the defendant arising from the substantive trial:
· Military Audiograms Vindicated
One of the most significant findings was the Court’s endorsement of military audiograms.
The Court concluded that while BSA-compliant pure tone audiometry remains the gold standard, military screening audiograms can be relied upon for both diagnostic and quantification purposes where they form part of a consistent pattern. The Court expressly noted that, at the beginning of the trial, there had been considerable reluctance from the claimants and some of their experts to place weight on such audiograms.
Given that virtually all service personnel undergo hearing testing throughout their military career, the Court recognised that this finding could have significant consequences across the cohort. Historic military hearing records remain highly relevant and reliable evidence capable of informing both diagnosis and quantification.
The significance of this finding should also be viewed in conjunction with the Court’s conclusions on latency and acceleration. Together, those findings reinforce the importance of contemporaneous military hearing records when assessing what hearing loss was present during service and whether later deterioration can properly be attributed to military noise exposure
· Latency and Acceleration Arguments Rejected
The Court rejected the proposition that hearing loss continues to develop after hazardous noise exposure has ceased.
Mr Justice Garnham held that the theory was “a very long way from being proven in human beings” and confirmed that the orthodox view, namely that hearing loss does not progress after exposure ends, has not been displaced.
The Court regarded this as a clear success for the MOD. This significantly limits attempts to attribute later-life deterioration in hearing to historic military noise exposure – particularly where that exposure ceased many years (if not decades) prior.
· Cochlear Synaptopathy Rejected
The Court also rejected the claimants’ arguments regarding cochlear synaptopathy.
The judgment confirmed that cochlear synaptopathy cannot currently be definitively demonstrated or quantified in living humans and that no recognised diagnostic gold standard exists. The Court expressly recognised this issue as a defence success.
· Future Loss of Earnings: The Most Significant Defence Victory
Arguably the most important aspect of the judgment (and one which may have received less attention than the scientific findings) concerns the approach to future loss of earnings.
In the Lead Claim of Mr Lambie, the claimant sought a substantial award based upon an Ogden Tables approach, while the MOD contended that no future loss of earnings award should be made. The Court accepted neither primary position, instead awarding a significantly more limited Smith v Manchester-style award (limited to 12 months net earnings).
Crucially, the Court recognised that future earnings claims may represent the single largest head of loss for a significant proportion of the cohort. The Court expressly concluded that the effect of its ruling was “overwhelmingly positive for the defendant” because acceptance of the claimants’ Ogden approach would have increased the value of the overall cohort “very substantially indeed”.
In practical terms, this aspect of the judgment may prove to be one of the most significant outcomes of the litigation. While much of the commentary surrounding Abbott has understandably focused on diagnosis and quantification, the Court itself identified future loss of earnings as a potentially critical issue across the wider cohort. The costs judgment therefore provides further judicial endorsement of the significance of this defence success.
A further noteworthy aspect of the costs judgment was the Court’s treatment of the evidence provided by the claimants concerning the wider impact of the judgment.
The claimants sought to analyse a sample of remaining claims and assess the likely effect of the substantive judgment on the wider litigation. The Court, however, expressly cautioned against placing significant weight on such exercises. Mr Justice Garnham observed that attempts to quantify the impact of the judgment were inherently speculative, based upon incomplete information, and undertaken by individuals with an interest in the outcome.
The Court stated that it did not find efforts to quantify the overall impact particularly helpful and instead preferred to assess the judgment’s consequences at a higher level of generality.
This is an important observation. It demonstrates that the Court was unwilling to accept broad projections of success advanced by either party without objective evidential support. Rather, the Court reached its own assessment of the significance of the various findings and their likely effect on the cohort.
The Court also acknowledged the possibility that some of its findings may affect the willingness of certain claimants to continue pursuing claims. In particular, the Court observed that its conclusions on latency, acceleration, cochlear synaptopathy and de minimis hearing loss may lead some claimants to reconsider the viability of their cases. While the Court was careful not to speculate on numbers, it recognised that these findings may have practical consequences across the wider litigation.
While the claimants were awarded 60% of their common costs, the judgment makes clear that neither party can properly claim complete victory. Nor should the 60% costs award be viewed as a mathematical scorecard for the litigation. The Court repeatedly emphasised that this was not a conventional personal injury action and that success had to be assessed by reference not only to the issues won, but also to their significance and impact across the wider military NIHL cohort.
The Court recognised that the claimants succeeded on some of the critical scientific building blocks for diagnosis and quantification. Equally, however, the Court accepted that the MOD achieved substantial successes on issues with potentially significant cohort-wide consequences, particularly military audiograms, latency, acceleration, cochlear synaptopathy, and future loss of earnings.
The judgment therefore reinforces several important principles for the ongoing management of military NIHL litigation:
The costs judgment confirms that Abbott was not a case in which either side secured a complete victory. However, it also provides clear judicial recognition that the MOD achieved a number of important successes that are likely to shape the future landscape of military NIHL litigation.
In particular, the Court’s findings on military audiograms, latency and acceleration, cochlear synaptopathy, and future loss of earnings represent significant defence outcomes which will continue to influence the valuation, management and resolution of claims across the wider military hearing loss cohort.
Perhaps most importantly, the costs judgment confirms that the 60% costs award should not be regarded as a simple scorecard of success. Rather, it reflects the Court’s assessment of both the issues won and their likely significance across the wider cohort, reinforcing that a number of the MOD’s successes carried substantial and financial consequences.
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