The High Court has provided useful guidance on litigation capacity in KDS (by His Litigation Friend MRW) v EUI Limited [2026] EWHC 2329 (KB). The claimant suffered a mild traumatic brain injury and significant psychological injury following a fatal road traffic collision. Although he strongly maintained that he had capacity and wished to instruct his solicitors directly, the court concluded that he lacked capacity to conduct the litigation and should continue to act through a litigation friend. 

The decision turned not on whether the claimant could make everyday decisions, but whether he could understand, retain, use and weigh information required to make informed decisions in complex, high-value litigation. The Court accepted expert psychiatric evidence that, despite support and reasonable adjustments, the claimant's cognitive impairment, executive dysfunction and PTSD-related symptoms prevented him from reliably doing so.

Why is this case noteworthy?

The judgment appears, at first sight, to sit uneasily alongside the Court of Appeal's guidance in Folks v Faizey, where caution was expressed about determining litigation capacity as a standalone preliminary issue.

However, the facts in KDS were materially different.

Here, the claimant himself challenged the need for a litigation friend and sought a determination that he had capacity rather than it being an issue between legally represented parties that should be determined at trial. The court was therefore required to resolve a live issue affecting who could properly provide instructions, make settlement decisions and control the proceedings. The judge also recognised the importance of ensuring the claimant had an opportunity to challenge any finding that he lacked capacity, reflecting the procedural fairness considerations that arise when restricting a party's ability to conduct their own litigation. 

In that sense, KDS is best viewed not as a departure from Folks v Faizey, but as an exception driven by the circumstances of the case. Where a claimant actively disputes the need for a litigation friend, an early determination of capacity may be necessary and appropriate.

Key takeaways

• A claimant may be capable of making everyday decisions yet still lack capacity to conduct complex litigation.
• The crucial question remains whether the claimant can use and weigh relevant information, not merely understand it when explained.
• Psychological injury and PTSD may be as significant as brain injury when assessing litigation capacity.
• The decision highlights a potentially important exception to Folks v Faizey: where a claimant in person actively contests the need for a litigation friend, the court may need to determine capacity at an early stage.
• Capacity remains issue-specific and time-specific and should be kept under review as litigation progresses. 

For insurers and practitioners handling catastrophic injury claims, the case is a reminder that disputes regarding litigation capacity can have significant procedural consequences and, in limited circumstances, may justify determination before the substantive issues in the claim are resolved.