Calculating the unknowable: The High Court’s approach to children’s lost years claims after CCC

In JBX v Frimley Health NHS Foundation Trust [2026], the High Court considered how damages for a child’s “lost years” should be assessed following the Supreme Court’s decision in CCC v Sheffield Teaching Hospitals NHS Foundation Trust [2026]. The judgment offers important early guidance on the evidence and methodology likely to shape these claims going forward.

In CCC, the Supreme Court overruled Croke v Wiseman [1982] and confirmed that children whose life expectancy has been shortened by negligence may recover earnings lost during the period between their anticipated death and their uninjured life expectancy. The compensatory principle now applies to children on that front just as it does to adults.

JBX, handed down on 4 September 2026, is significant because it shows how that exercise may work in practice when the claimant was too young at the date of injury to have an established career path or earnings history.

The facts

The claim arose from admitted clinical negligence in the management of JBX’s asthma. He was eight years old when he was discharged from hospital; his condition deteriorated the following day, and he sadly suffered a cardiac arrest resulting in a catastrophic brain injury. The parties agreed that his life expectancy had been reduced to 25 and a half years from the norm. The court was therefore required to assess, among other heads of loss, the earnings he would probably have received during the “lost years”.

The competing approaches

The claimant argued that his likely earnings should be assessed above the national average figures. He relied on his educational progress evidenced by school reports, his family’s occupational achievements and local employment conditions. On that basis, he invited the court to assume the claimant would follow a similar career trajectory as his father who had a successful career in the city as a salesman and to deduct 50% of net earnings for personal living expenses, reflecting the conventional approach often taken in adult claims.

The defendant argued that average earnings data should be used instead. It also argued that 90% deduction for the “lost years” was appropriate in light of the substantial uncertainty surrounding a young child’s future career and expenditure, together with the Supreme Court’s observation in CCC that the deduction in such cases might be high to account for the uncertainty.

The High Court’s decision

The court determined average earnings (ie, the latest Annual Survey of Hours and Earnings available) as the appropriate basis for calculating JBX’s potential earnings. Those earnings should be calculated to a retirement age of 70 on the basis the national retirement age will only ever increase in future, and that a 50% deduction on the “lost years” part of the award was appropriate.

Earnings: Evidence must justify departure from the average

While the headline decision itself is telling, the real value of the judgment is in the discussion of the court’s approach.

The court was not satisfied that there was enough evidence to assume that JBX would have followed his father’s career. The fact that his older brother had taken a different route illustrated the difficulty of drawing conclusions from parental occupation alone. JBX’s early school reports also provided limited assistance in predicting his eventual employment or earnings.

Importantly, the court did not reject the possibility of assessing a child’s earnings above the national average by reference to family background or a particular career path. Rather, it declined to do so on the facts because there was insufficient evidence that JBX would have followed his father’s career. A claimant may therefore still pursue an above-average earnings claim where there is clear evidence that the suggested career path is realistic rather than speculative, though it seems persuading the court to depart from national average data may prove a tricky task.

Living expenses: No automatic enhanced deduction

The court rejected the Trust’s proposed 90% deduction. It considered that uncertainty about a child’s future expenditure did not, without more, justify a deduction far outside the range ordinarily seen in adult lost years claims. A 50% deduction was appropriate on the facts.

However, the judge cautioned against the “reflexive use” of a conventional figure. The decision does not establish 50% as a default for child claimants: the appropriate deduction may be higher or lower depending on the evidence in the individual case. It will, therefore, no doubt be a particular point of dispute in these claims going forwards given a small chance in the percentage deduction can lead to enormous shifts in the damages a claimant may receive.

Why the decision matters

JBX highlights the need to consider the value of lost years claims at an early stage. Average earnings may provide a sensible starting point where a child has no established career path, but any proposed departure, whether in the assumed level of earnings or the deduction for living expenses, will require evidence tailored to the individual claimant.

Equally, although this represents the start of the story in assessing these claims after CCC, it seems national average data (which is far more extensive and reliable than at the time of Croke v Wiseman [1982]) may become a common starting point in such claims. Of course, which party might be seeking to depart from that will depend on whether that departure would represent and increase or decrease to the claim.

As such, even if you find yourself defending such a claim, it may well be worth pushing for that evidence going to what a claimant would otherwise have earned.

Conclusion

JBX is an important first application of the principle established in CCC.

It suggests that the courts will take a pragmatic but evidence-led approach: statistical averages may fill the gap where a child’s future is necessarily uncertain, while departures from those averages will require persuasive support.

The central lesson for practitioners is not that one methodology or percentage will govern every claim, but that careful, case-specific evidence will drive the valuation and that it isn’t necessarily only claimants that should be pushing for evidence going to lost earning capacity.

For more information or to discuss any of the above, please get in touch with our insurance claims and disputes team.

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