The judgment in Abbott and Others v Ministry of Defence [2026] EWHC 941 (KB) is one of the most significant developments in military noise-induced hearing loss litigation for years.
It provides detailed guidance on:
- the diagnosis of military NIHL;
- the reliability and use of military audiograms;
- the quantification of hearing loss;
- tinnitus;
- de minimis injury;
- hearing aids;
- general damages;
- and future loss of earnings.
For claimant solicitor firms, the judgment will affect more than the valuation of damages.
It is likely to shape the medical evidence obtained, the records reviewed, the questions asked of experts, the advice given to claimants and the work required to progress MoD NIHL files towards settlement. That has an obvious costs consequence. However, an important distinction must be made at the outset: Abbott is not a costs judgment.
It does not decide what hourly rates are recoverable, how much time should be allowed in a bill or whether any particular expert fee must be paid. The costs significance is indirect but substantial. The judgment helps define the work that may reasonably be required in MoD NIHL costs drafting after April 2026.
What Was Abbott v Ministry of Defence About?
The litigation concerned claims brought by former members of the Armed Forces who alleged that exposure to excessive noise during military service caused noise-induced hearing loss and tinnitus. The judgment followed the trial of two remaining test cases and a series of generic issues intended to provide guidance across a much larger cohort.
By the time of judgment, the total number of military NIHL claims stood at 10,440.
The litigation was not formally subject to a Group Litigation Order, but it had many similar features, including:
- common case management;
- a group register;
- generic issues;
- common costs;
- lead cases;
- and issues intended to bind or guide the wider cohort.
The hearing involved extensive technical and expert evidence across audiology, ENT medicine, epidemiology, auditory physiology, acoustics, hearing aids and employment loss.
What Was the MoD NIHL Matrix?
Before Abbott was decided, the claimants and the Ministry of Defence reached an agreement dealing with several recurring issues. The agreement was referred to as the Matrix. It addressed matters including:
- Crown immunity;
- combat immunity;
- breach of duty;
- contributory negligence;
- apportionment;
- noise immission levels;
- and limitation.
In return for a structured discount on damages, the Matrix left causation and quantum to be determined. Abbott therefore dealt mainly with the medical, evidential and valuation issues that remained.
The Matrix remains important to costs because it may reduce the work required on some liability issues. But it does not mean that every MoD NIHL claim becomes straightforward — as we explain in MoD NIHL costs after Matrix settlement. Causation, audiology, tinnitus, hearing aids, quantum and individual circumstances can still require detailed work.
The Main Findings in Abbott
The judgment is lengthy and technically detailed. For claimant firms, the following findings are among the most important.
The rM-NIHL Method Was Preferred
The Court preferred the rM-NIHL method for diagnosing military noise-induced hearing loss. It held that the traditional CLB method was not generally suitable for military cases. This matters because military noise exposure is often different from ordinary civilian industrial exposure. Military personnel may be exposed to:
- gunfire;
- explosions;
- artillery;
- aircraft;
- armoured vehicles;
- heavy weapons;
- impulsive noise;
- and asymmetric exposure.
The preferred diagnostic method must therefore reflect the particular features of military service rather than simply importing a civilian industrial model.
The costs consequence. Claimant firms may need to review whether existing medical evidence applies the correct methodology. That may require:
- reviewing existing ENT reports;
- obtaining supplemental reports;
- asking further questions;
- reconsidering causation advice;
- reviewing audiograms again;
- reassessing settlement offers;
- and updating schedules of loss.
Where this work is reasonably required because of Abbott, it should be recorded clearly on the file. A paying party may later argue that the work was unnecessary or duplicated. The bill should explain why the judgment required the evidence or advice to be reconsidered.
Military Audiograms Remain Important
The Court held that British Society of Audiology-compliant pure tone audiometry remains the gold standard where available. However, military screening audiograms are not automatically unreliable. They may be used for diagnosis and quantification where they form part of a consistent pattern and are considered through proper clinical judgment. The Court also recognised that systemic or operational inadequacies may occur in some cases.
The correct approach is therefore not to accept or reject military audiograms automatically. They should be reviewed:
- in context;
- as part of the wider series;
- against later audiometry;
- alongside the claimant’s service history;
- and with appropriate expert interpretation.
The costs consequence. The judgment supports careful, file-specific review of military audiometric records. A MoD NIHL bill may therefore need to reflect time spent:
- identifying relevant audiograms;
- organising the audiometric chronology;
- comparing service and civilian tests;
- reviewing apparent inconsistencies;
- obtaining expert comment;
- and considering whether the evidence forms a reliable pattern.
Generic entries such as “review medical records” are unlikely to explain this work adequately. Better descriptions should identify the purpose of the review. For example:
- reviewing military audiometric series to identify changes during service;
- comparing military screening audiograms with later BSA-compliant testing;
- considering expert comments on the reliability of the claimant’s service audiograms;
- reviewing audiometric evidence following Abbott diagnostic guidance.
Quantification Must Remain Individual
The Court preferred the Moore, Cox and Lowe method of quantification. It confirmed that the conventional average across 1, 2 and 3 kHz remains a useful baseline descriptor. However, supplementary measurements incorporating 4 kHz may also be relevant, particularly where speech-in-noise difficulty is prominent. The Court also indicated that the usual 4:1 binaural calculation should generally be used, but that clinicians and courts must consider whether it fully captures the claimant’s actual disability.
The costs consequence. Damages advice may now require more than inserting a decibel figure into a standard calculation. Claimant solicitors may need to consider:
- alternative frequency averages;
- asymmetric loss;
- speech-in-noise difficulty;
- the claimant’s functional evidence;
- expert explanation;
- and whether the standard calculation reflects the full disability.
This may justify further medical review and more detailed claimant instructions. But it does not justify unnecessary repetition. The file should show what issue required the additional work and how that work affected advice or settlement.
Delayed Progression Was Not Established
The Court considered whether hearing loss could continue to develop after exposure to harmful noise had ended. It found that the theory was plausible but had not been established in humans. The orthodox position that NIHL does not continue to progress after exposure ceases was not displaced. The Court also found that there was no reliable method for identifying or quantifying such progression in an individual claimant.
The costs consequence. Claimant firms should be cautious about incurring substantial expert costs pursuing acceleration or delayed-progression arguments without a proper evidential basis. After Abbott, a paying party may challenge:
- supplemental reports on acceleration;
- extensive expert questions;
- specialist evidence;
- or time spent advancing unsupported progression theories.
The safest approach is to assess whether the work remains justified on the individual evidence.
Cochlear Synaptopathy Remains Difficult to Prove
The Court held that cochlear synaptopathy cannot presently be demonstrated or quantified definitively in living humans. There is no accepted gold-standard test.
The costs consequence. Work based solely on an unproven synaptopathy theory may face a strong recoverability challenge. Claimant firms should distinguish between:
- a genuine functional difficulty supported by evidence;
- and a speculative medical theory without an accepted diagnostic basis.
Where specialist evidence is obtained, the file should explain why it was reasonably required at the time. The reasonableness of costs is assessed in light of the information available when the work was undertaken, not solely with hindsight. But Abbott will be highly relevant to work undertaken after the judgment.
No Arbitrary Cut-Off for Tinnitus
The Court rejected a rigid time limit beyond which tinnitus could never be linked to military noise exposure. It accepted that delayed-onset tinnitus is possible. However, the longer the gap between exposure and the onset of tinnitus, the closer the factual and medical scrutiny must be. Tinnitus remains a subjective condition. The quality and consistency of the claimant’s history will therefore be central.
The costs consequence. Tinnitus claims may require detailed instructions on:
- when symptoms first appeared;
- whether symptoms were intermittent or continuous;
- whether they were reported during service;
- whether there were alternative causes;
- the relationship with hearing loss;
- treatment;
- and functional impact.
This can justify meaningful client attendance and medical review. But the bill should describe the purpose of the work. Repeated generic telephone calls will be vulnerable. Specific entries are stronger, such as:
- taking detailed instructions on tinnitus onset and progression;
- reviewing service medical records for contemporaneous tinnitus complaints;
- considering alternative causes identified in the ENT report;
- advising on causation risk following delayed symptom onset.
The Four-Decibel De Minimis Issue
The Court held that hearing loss below 4 dB, without other consequences, should generally be treated as de minimis. However, it left open the possibility that loss below that level could still cause appreciable damage in an individual case.
The costs consequence. Files involving low levels of quantified NIHL need early merits review. Claimant firms should consider:
- the measured loss;
- tinnitus;
- asymmetry;
- speech-in-noise difficulty;
- functional evidence;
- expert opinion;
- and whether there are other material consequences.
Continuing a weak claim without proper review may create costs risk. Conversely, the presence of credible additional consequences may justify further investigation even where the numerical loss is below 4 dB. The bill should show that the issue was considered rather than ignored.
General Damages Remain Fact-Sensitive
The Court confirmed that the Judicial College Guidelines remain the appropriate starting point for general damages. The measured decibel loss is highly relevant but does not determine the damages bracket by itself. The court must also consider the practical effect of the injury. That may include:
- communication difficulty;
- speech-in-noise problems;
- tinnitus;
- effect on family life;
- employment consequences;
- hearing aid use;
- loss of confidence;
- and reduced social participation.
The costs consequence. A proper damages assessment may require more detailed claimant instructions than a simple review of the audiogram. This supports carefully recorded work on functional impact, daily activities, employment, relationships, social situations, hearing aid experience and future risk. The key is relevance — the work should connect directly to quantum and settlement advice.
Private Hearing Aids May Be Recoverable
The Court accepted that a claimant may, depending on the individual evidence, justify the cost of private, high-performance rechargeable hearing aids. The judgment referred to current costs in the region of £4,200 to £5,000, including fitting and related items. But the Court did not establish an automatic entitlement. The need for hearing aids, specification, replacement cycle and ancillary equipment remain case-specific.
The costs consequence. Hearing aid claims may require specialist hearing aid evidence, quotations, trial information, replacement assumptions, claimant instructions, consideration of NHS provision and a reasoned schedule of loss. A generic hearing aid claim without individual evidence may be challenged. The bill should show why expert or audiological work was needed on that claimant’s facts.
Future Earnings Claims Require Individual Evidence
The Court did not establish a generic rule for future loss of earnings. Such claims remain highly fact-sensitive. Claimant firms should consider:
- occupation;
- current employment;
- qualifications;
- career plans;
- restrictions;
- workplace communication;
- risk of future disadvantage;
- alternative employment;
- and expert employment evidence.
The costs consequence. Employment expert evidence should not be obtained automatically on every file. It may be reasonable where there is a genuine issue. It may be disproportionate where the claim is speculative or unsupported. The file should record why the evidence was commissioned.
Abbott Does Not Automatically Increase Recoverable Costs
The judgment is important, but claimant firms should not assume that every post-Abbott file justifies more time or more expert evidence. Recoverable costs remain subject to the usual principles of reasonableness, proportionality, necessity, appropriate delegation and evidential support.
On the standard basis, costs can be reduced even where the work was genuinely carried out. The question will be whether the work bore a reasonable relationship to:
- the sums in issue;
- the complexity of the claim;
- the importance of the matter;
- the conduct of the parties;
- and any wider factors relevant to the proceedings.
Abbott may support additional work where the judgment genuinely required evidence or advice to be revisited. It will not protect unnecessary or duplicated work. (See our guide to the Guideline Hourly Rates 2026 for more on rates and proportionality.)
Military NIHL Claims and Fixed Costs
Military NIHL claims are expressly excluded from the specific fixed recoverable costs regime for ordinary NIHL claims under Annex E of the Disease and Illness Pre-Action Protocol. That does not mean every item claimed is recoverable. It means the military claim should not simply be forced into the ordinary NIHL fixed costs table.
Where costs are recoverable on the standard basis, they must still be:
- reasonably incurred;
- reasonable in amount;
- proportionate;
- and properly evidenced.
For claimant firms, this makes bill quality particularly important.
What Should a Post-Abbott MoD NIHL Bill Include?
A properly prepared bill should explain the actual work required on the file. Depending on the case, the narrative may include:
- the claimant’s branch and service history;
- relevant military noise exposure;
- weapons, vehicles or aircraft involved;
- military audiograms;
- later audiometric evidence;
- ENT evidence;
- the diagnostic method used;
- tinnitus evidence;
- hearing aid recommendations;
- Matrix application;
- settlement history;
- costs entitlement;
- damages outcome;
- and any Abbott-related review.
The bill should not simply mention Abbott to justify a higher total. It should identify the specific work generated by the judgment.
Examples of Abbott-Related Time Entries
Weak entries include:
- review Abbott;
- consider judgment;
- review medical evidence;
- update report;
- advise client.
Stronger entries include:
- reviewing ENT report against Abbott guidance on the rM-NIHL diagnostic method;
- comparing claimant’s military audiograms with later BSA-compliant audiometry following Abbott;
- considering whether quantified loss falls within the de minimis guidance and whether tinnitus produces additional appreciable damage;
- reviewing hearing aid recommendation against Abbott guidance on private high-performance devices;
- advising claimant on the effect of Abbott on tinnitus causation and settlement prospects;
- drafting targeted questions to the ENT expert on military audiogram reliability and quantification.
Specific descriptions show why the work was required.
Should Existing MoD NIHL Files Be Reviewed?
Yes, but proportionately. Claimant firms should consider reviewing files where:
- the ENT report used the CLB method;
- causation was rejected under a civilian diagnostic model;
- military audiograms were discounted automatically;
- hearing loss was quantified without considering the wider audiometric series;
- delayed tinnitus was rejected solely because of time;
- a low-value hearing loss was treated as automatically non-actionable;
- hearing aid claims were rejected without individual assessment;
- offers were based on medical assumptions affected by Abbott.
Not every file will need a new report. Some may require only a short expert clarification. Others may require no further work. The decision should be made file by file.
How Paying Parties May Use Abbott
Abbott contains findings that may assist both sides. Paying parties may rely on:
- the rejection of continuing progression after exposure;
- the difficulties proving cochlear synaptopathy;
- the de minimis guidance;
- the need for case-specific hearing aid evidence;
- closer scrutiny of delayed tinnitus;
- and the requirement for individual proof of future loss.
Receiving parties should not present Abbott as a complete claimant victory. The judgment is mixed and evidence-specific. A credible bill and Reply should recognise the adverse points as well as the helpful ones.
How Claimant Firms Can Protect Recovery
The strongest approach is to record the reason for the work as it happens. Claimant firms should:
- identify which Abbott issue affects the file;
- record why the existing evidence is insufficient;
- keep expert questions focused;
- avoid obtaining duplicated reports;
- take detailed but relevant claimant instructions;
- review proportionality before commissioning evidence;
- preserve all expert invoices;
- record the advice given on risk;
- explain any change in case strategy;
- link additional work to settlement or progression.
This gives the costs draftsman a proper foundation for the bill.
Documents to Send to the Costs Draftsman
For a post-Abbott MoD NIHL file, provide:
- the Letter of Claim;
- service history;
- military audiograms;
- civilian audiograms;
- ENT reports;
- audiology reports;
- hearing aid evidence;
- expert invoices;
- questions to experts;
- Matrix documents;
- offers;
- settlement agreement;
- damages calculation;
- costs correspondence;
- fee earner details;
- hourly rates;
- relevant Abbott review notes.
The costs draftsman should be able to identify what work was generated by the case and why it was required.
Does the Matrix Cap Costs After Abbott?
No automatic costs cap follows from Abbott or the Matrix. The Matrix addressed substantive issues and structured damages resolution. It did not convert every military hearing loss claim into a fixed-cost matter. The recoverable costs position will depend on:
- the settlement wording;
- the applicable costs order;
- the work actually undertaken;
- reasonableness;
- proportionality;
- the available evidence;
- and the outcome achieved.
Claimant firms should avoid settling costs by reference to damages alone. Costs and damages are separate issues. Where damages settle pre-issue but costs remain unresolved, CPR 46.14 costs-only proceedings may need to be considered.
The Main Costs Takeaways From Abbott
- Abbott is not itself a costs judgment.
- It may justify targeted review of existing medical evidence.
- The rM-NIHL method is preferred for military cases.
- Military audiograms must be considered in context.
- Quantification remains clinically and factually sensitive.
- Delayed tinnitus is not barred by a rigid time limit.
- Loss below 4 dB requires careful merits review.
- Hearing aid claims require individual evidence.
- Future earnings claims remain highly fact-sensitive.
- Post-Abbott work must still be reasonable and proportionate.
- Military NIHL claims remain excluded from the specific ordinary NIHL fixed costs regime.
- Bills should explain exactly what work Abbott generated.
How DMD Costs Can Help
DMD Costs works with claimant solicitor firms on MoD NIHL and military hearing loss costs. We can assist with:
- MoD NIHL bills of costs;
- Matrix settlement costs;
- Precedent S electronic bills;
- N252 and Notice of Commencement;
- medical and audiology disbursement disputes;
- hearing aid evidence costs;
- Points of Dispute;
- Replies;
- proportionality arguments;
- hourly rate disputes;
- costs-only proceedings;
- settlement-led negotiation.
If Abbott has led to further medical review, updated evidence or renewed settlement discussions, send us your MoD NIHL costs file. We will present the work clearly and progress the costs towards recovery.