Briefing Note: JBX v Frimley Health NHS Foundation Trust [2026] EWHC 2294 (KB)

JBX appears to be the first reported High Court assessment of a child claimant's lost years claim following the Supreme Court's decision in CCC v Sheffield Teaching Hospitals NHS Foundation Trust [2026] UKSC 5 to allow the award, overruling Croke v Wiseman [1982] 1 WLR 71.

As such, it provides the first judicial indication of how courts may approach the practical valuation of these claims and is likely to be of significant interest to compensators when assessing future quantum exposure.

Applying the framework contemplated in CCC, Andrew Kinnier KC (sitting as a Deputy High Court Judge) approached the calculation using the traditional multiplier-multiplicand methodology. The principal dispute concerned (i) the appropriate earnings basis and (ii) the percentage deduction for the claimant's own living expenses. 

On earnings, the claimant argued that the court should assume a career trajectory similar to his father's successful City sales career and thus substantially higher than average earnings. The judge rejected that approach as too speculative.

He considered that the evidence did not safely support a conclusion that the claimant would have followed his father's path, particularly given that his older brother had taken a very different route. Instead, the court adopted ASHE Average Weekly Earnings data (published by the Office for National Statistics) as the appropriate evidential benchmark. The decision reinforces the importance of robust evidential support where claimants seek to advance earnings assumptions materially above population averages and may provide defendants with a useful starting point when challenging ambitious career assumptions.

Perhaps of greater significance for future claims was the appropriate deduction for the claimant's own living expenses, described by the judge as a “controversial question”. In CCC, Lord Burrows had suggested that, in claims involving young children, a relatively high and "rough and ready" deduction might often be required because of the inherent uncertainty involved in predicting future expenditure. However, in JBX the court declined to accept that this uncertainty justified the 90% deduction proposed by the Trust.

The judge held that such a figure was inconsistent with the range of deductions typically applied in adult lost years cases and instead applied a 50% deduction. In doing so, the court declined to treat childhood uncertainty as justifying a radically enhanced deduction. Although 50% is not an uncommon figure in such claims, the judge stressed that 50% should not become a default, cautioning “against the reflexive use of a conventional figure” and emphasising that the appropriate deduction remains fact-sensitive.

The decision in JBX suggests that the courts may adopt a relatively orthodox approach to quantification notwithstanding the novelty of child lost years claims following CCC. While the Supreme Court recognised the substantial uncertainties inherent in valuing a child's future earnings and expenditure, JBX suggests that uncertainty alone may not be sufficient to justify substantial reductions in the value of child lost years claims absent supporting evidence. 

Future disputes are likely to focus less on abstract uncertainty and more on the evidential basis for competing assumptions regarding earnings and expenditure. The valuation exercise remains evidence-driven, and the judgment may offer parties and their advisers a degree of reassurance that conventional lost years principles will continue to provide the starting point.

The significance of JBX is not that it fixes a standard deduction for child lost years claims, but that it indicates courts are likely both to apply orthodox lost years principles and valuation assumptions and to require clear supporting evidence before departing from them.

Practice Points

• Claims reserves in cases involving minors with materially shortened life expectancies should be reviewed to account for the potential addition of a lost years claim following CCC. Even where earnings evidence is limited, JBX confirms that in appropriate cases lost years claims now represent a potentially significant additional head of loss.
• The lost years award in JBX was calculated using a multiplier and multiplicand. Although this does not entirely close the door on using a “broad brush” approach – which Lord Burrows observed in CCC is sometimes retained for other heads – it provides an indication that courts may regard the multiplier-multiplicand methodology as the natural starting point in future cases.
• Where claimants contend for earnings materially above national averages, compensators should seek early disclosure of educational records, attainment evidence, family employment history, and other material directly relevant to projected career trajectories.
• The appropriate deduction for living expenses is likely to become a key battleground in future claims. Parties should consider obtaining evidence capable of informing future expenditure patterns rather than relying solely on conventional percentage deductions.
• Insurers and clinical compensators should be cautious about assuming that the uncertainties associated with child claimants will justify substantial deductions for living expenses. JBX suggests that courts may require a clear evidential basis before departing materially from established lost years authorities.