The recent decision of Mr Justice Cotter in Williams v Wilkinson [2026] EWHC 1088 (KB), provides a detailed and robust analysis of the principles governing very late amendments, particularly where they would imperil a fixed trial date and fundamentally recast the causation case. Consistent with that approach, the court refused the Claimant’s late application to amend her case on causation.
DWF’s Healthcare Team acted for the Defendant Osteopath, instructed by Zurich Insurance, and worked closely with the insurer throughout. Anna Hughes of 2 Temple Gardens was instructed by DWF as counsel.
Background
The Claimant brought a clinical negligence claim against an osteopath, alleging failure to advise urgent attendance at A&E during a consultation during the evening of 14 February 2020. Breach of duty was admitted pre‑issue, but causation was disputed.
The Claimant contended that, had she been properly advised, she would have reached hospital earlier, undergone emergency surgery sooner, and avoided significant residual neurological deficits. Surgery in fact took place at 16:10 on 15 February 2020.
The claim was listed for a 7‑day trial commencing 15 June 2026, with expert evidence already exchanged and joint statements prepared.
The application
By an application dated 16 April 2026, the Claimant sought permission to:
- Amend her Particulars of Claim to plead an alternative case on factual causation;
- Rely on additional factual witness evidence (including a further statement from herself and evidence from her solicitor);
- Rely on further expert evidence from spinal, urology and pain experts.
Crucially, the Claimant sought to abandon her original case that she would probably have undergone surgery on the evening of 14 February 2020 and sought permission to instead advance an alternative case that, with reasonable care, surgery would have taken place overnight or at around 09:00 on 15 February 2020, being some 6–7 hours earlier than in fact occurred.
It was common ground that if permission to amend were granted, the trial date would be lost.
Key issues for the Court
Mr Justice Cotter focused on three interlinked questions:
- Was the amendment “very late”?
- Did the proposed amended case have real prospects of success?
- How should the balance of injustice be struck under the overriding objective?
Decision and reasoning
The application was refused in its entirety.
1. The amendment was very late
The Court held that this was a paradigm example of a “very late” amendment:
- The trial date was fixed.
- Allowing the amendment would necessarily result in adjournment.
- The case was close to trial and fully prepared on the basis of the original pleaded case.
The authorities in Quah v Goldman Sachs, Nesbit Law Group v Acasta, and Pearce v East & North Hertfordshire NHS Trust were applied, emphasising that parties and the court are entitled to expect trial fixtures to be maintained.
2. No good explanation for lateness
The Claimant argued that the need for amendment only crystallised after the spinal experts’ joint meeting. This was rejected.
The Court found that:
- Factual causation was always central to the claim.
- The Claimant’s own evidence showed she would likely have gone home, waited for childcare support, and experienced delay.
- The Defendant’s spinal expert had flagged the factual causation difficulties clearly in October 2025.
- The timing of the actual surgery and issues in relation to prioritisation of that surgery on the morning of 15 February 2020 were well known long before the application.
The failure to analyse and plead these issues earlier was “not a good reason” for the late application.
3. The amended case was speculative and incomplete
While the Court stopped short of holding the amendment was bound to fail, it found its prospects highly uncertain:
- The amended pleading did not adequately address when the Claimant would have called NHS 111 or 999.
- There was no clear evidential basis for asserting that surgery would probably have taken place during the night or at 09:00.
- The proposed case failed to grapple with the reality that, even once diagnosed, the Claimant had not been prioritised for immediate surgery in fact.
- Significant further factual and expert work would be required, including potentially expert evidence on NHS 111 processes.
Mr Justice Cotter described the amendment as “the best that could be done at present” and effectively a holding position - a factor weighing against permission.
4. Prejudice and the overriding objective
Allowing the amendment would:
- Cause the loss of the trial date;
- Require extensive further evidence and expert reconsideration;
- Delay resolution potentially until 2027, more than six years after the events;
- Allocate a disproportionate share of court resources.
Although breach was admitted and the claim was high value, that did not outweigh the structural unfairness to the Defendant and the wider court system.
Key takeaways
- Causation must be fully analysed and pleaded early, especially in cases such as this where timing and counterfactual pathways are central.
- The burden of establishing causation in clinical negligence cases rests on the Claimant. The Defendant is reasonably entitled to respond to the pleaded case and there is no onus on the Defendant to address a factual causation issue which had not been pleaded.
- Documents disclosed during the course of proceedings are to be treated as evidence in the claim unless challenged.
- Very late amendments face a heavy burden, even in serious, high‑value clinical negligence claims. The court will not permit amendments simply to avoid a weak or untenable pleaded case where the difficulty arises from the Claimant’s own failure to analyse the evidence in time.
- Loss of a fixed trial date is a powerful, and often decisive, factor against permission.
- Claimants cannot rely on hoped‑for further evidence as justification for late reformulation of their case.
Conclusion
This judgment reinforces the modern, disciplined approach to late amendments under the CPR. Even in cases involving admitted breach and serious injury, the court will prioritise procedural fairness, trial certainty, and proportionality over allowing late attempts to rescue an unsustainable causation case.
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