In February 2026, the Court of Appeal handed down its judgment in the case Adcamp LLP v Office Properties PL Limited & Ors [2026] EWCA Civ 50 concerning the limits on when a party can be added to or substituted in a claim after the expiration of a limitation period. Senior Associate Elisa Wahnon reviews the decision.

The issue of adding or substituting a party often arises in securities litigation, as claims are frequently issued on or close to an arguable limitation deadline. So, changing a claimant’s name often leads to a debate about what is permissible under Civil Procedure Rule (CPR) CPR 19.6, which governs the addition or substitution of parties after the end of an arguable limitation period.

The Court of Appeal’s judgment was in respect of two appeals heard together: Office Properties PL Limited v Adcamp LLP and Mark William Lee and another v BDB Pitmans LLP and another. Both arose from a common factual scenario involving allegations of professional negligence regarding advice provided by Pitmans LLP (Pitmans).

Key takeaways

• Mistake of identity vs name: a claimant’s mistaken belief that a successor firm had assumed the legal liabilities of a predecessor constitutes a mistake as to identity, not a mistake as to name. It therefore falls outside the ‘first gateway’ for substitution under CPR 19.6(3)(a), which allows the court to substitute a party who was named in the claim form by mistake.
• Restriction of the ‘second gateway’: CPR 19.6(3)(b) permits substitution only where it is necessary to maintain the original claim. A claim against a successor firm is legally distinct from a claim against the original firm. A claim against the successor firm could only be brought on the basis that the successor firm had assumed responsibility for those liabilities (for example, through novation of liabilities).
• Insight Group Ltd v Kingston Smith [2012] EWHC 3644 (QB): the Court of Appeal disagreed with obiter comments made by Mr Justice Leggatt in Insight Group, which had suggested a broader approach to correcting such errors via the second gateway.

Background

In December 2018, Pitmans’ partnership business was acquired by Bircham Dyson Bell LLP, which then changed its name to BDB Pitmans LLP (BDB). Crucially, there was no novation of liabilities from Pitmans to BDB. Pitmans subsequently changed its name to Adcamp LLP, was dissolved in 2021, and was restored to the register in 2023.

The claimants in both actions issued proceedings against BDB before the expiry of the limitation period. They did so under the mistaken belief that BDB had, as a matter of law, assumed responsibility for Pitmans’ pre-acquisition liabilities. When BDB defended the claims on the basis that it was the wrong defendant, the limitation period for bringing a new claim against Pitmans (Adcamp) had expired.

The claimants applied to substitute Pitmans for BDB under CPR 19.6. The respective High Court judges both allowed the substitution under CPR 19.6(3), relying heavily on the obiter reasoning of Mr Justice Leggatt in Insight Group. Pitmans and BDB appealed, arguing that the High Court had impermissibly expanded the scope of the rule to allow entirely new claims to be brought after the limitation period had expired.

The decision

The Court of Appeal allowed the appeals and set aside the orders for substitution.

The first gateway: mistake of name vs identity

The Court of Appeal first addressed CPR 19.6(3)(a), which allows substitution to correct a mistake as to the identity of a party named in the claim form. It was common ground that the claimants intended to sue BDB because they believed BDB had assumed responsibility for Pitmans’ liabilities. Citing The Sardinia Sulcis [1991] 1 Lloyd’s Rep 201 and Adelson v Associated Newspapers Ltd [2007] EWCA Civ 701; [2008] 1 WLR 585, the court confirmed this was a mistake of identity (a mistake of law regarding who was liable), not a mistake of name.

The Court of Appeal acknowledged Mr Justice Leggatt’s criticisms in Insight Group of the difficulties in distinguishing between errors of fact and law. However, it was common ground that it was not open to either claimant to contend that their case fell within the first gateway.

The second gateway: “the claim”

The central issue was the ‘second gateway’ under CPR 19.6(3)(b). The court had to determine whether the claim against Pitmans was the “same claim” as the one originally brought against BDB.

The respondents argued that “the claim” referred broadly to the underlying negligence and loss. The appellants argued that “the claim” encompassed all the facts asserted by the claimant, which, if established, would give rise to liability against the defendant, including the facts upon which it is asserted that the particular defendant was liable.

The Court of Appeal agreed with the appellants. It held that the claim against BDB relied on specific averments, namely, that BDB had assumed the liabilities of Pitmans (via novation, estoppel or acknowledgement). A claim against Pitmans would not require these facts but would instead rely solely on Pitmans’ own acts of negligence. Although both the original and proposed new claims were based on the same alleged duty, breach and loss, the original claim was one against BDB (for damages caused by the negligence of Pitmans) and the new claim was one against Pitmans (for damages caused by its own negligence), and those are two different claims.

The court distinguished the present facts from Parkinson Engineering Services plc v Swan [2009] EWCA Civ 1366; [2010] Bus LR 857 and Irwin v Lynch [2010] EWCA Civ 1153. In those cases, substitution was permitted because the cause of action remained identical; the issue was merely one of standing or procedural capacity. In Parkinson, the liquidator was substituted for the company to pursue the company’s own cause of action, which would otherwise have been defeated by a statutory release defence. In Irwin, the company was substituted for the administrator, who lacked standing to bring a misfeasance claim.

In both cases, the claim before and after substitution was the same in every material respect. Here, by contrast, the substitution involved a substantive change in the defendant’s identity and the legal basis of their liability.

Insight Group

The Court of Appeal explicitly addressed the obiter comments of Mr Justice Leggatt in Insight Group, where he suggested that substituting a predecessor firm for a successor LLP (where the mistake concerned who had assumed liability) should be permitted under the second gateway.

The Court of Appeal held that this reasoning was incorrect. A claim asserting BDB is liable for Pitmans’ negligence is not the “same claim” as one asserting Pitmans is liable for its own negligence. The proposed substitution was not designed to maintain the original claim. It was, as Lady Justice Hallett put it in Nemeti v Sabre Insurance Co Ltd [2013] EWCA Civ 1555, “designed to launch a new claim against a new party”.

Consequently, the condition that the substitution was “necessary for the determination of the original action” was not met. The original action against BDB failed on its own merits because BDB was not liable; substituting Pitmans was an attempt to bring a new claim against a new party out of time.

Commentary and practical implications

This judgment represents a tightening of the judicial approach to limitation and party substitution.

The court also reiterated that certain substitutions are outside the scope of CPR 19.6 as limitation is not engaged: namely, where, after proceedings have begun, either the claimant’s interest in, or the defendant’s liability for, a claim is transferred to a new party, whether by assignment, novation or according to a statutory merger or transfer of liabilities.

In Roberts v Gill [2010] UKSC 22; [2011] 1 AC 240, at §104 to §106, Lord Walker referred with approval to Mr Justice Mance’s analysis in The Choko Star [1996] 1 WLR 774 and to the decision of the Court of Appeal in the Yorkshire Regional Health Authority v Fairclough Building Ltd [1996] 1 WLR 210, to the effect that no question of limitation arises in the case of an assignment or transmission of a cause of action after proceedings have been commenced.

The Court of Appeal concluded that neither section 35(6) of the Limitation Act 1980 nor CPR 19.6 is intended to deal with a case where a claim is properly constituted within the limitation period and there later arises a need to substitute either the claimant or defendant because of a subsequent transfer of the interest in or liability for the claim. That is because such an event gives rise to no limitation issue in the first place.

For practitioners, Adcamp necessitates a review of pre-action due diligence and pleading strategies:

1. Successor liability traps: when suing an entity that has undergone a merger or acquisition, never assume liabilities transferred automatically. The mere acquisition of a “business” does not equate to the acquisition of pre-existing liabilities or the transfer of a cause of action.
2. Protective proceedings: if there is any ambiguity regarding the correct defendant or claimant and the limitation period is imminent, practitioners should issue proceedings against or in the name of all potential entities. It is safer to discontinue a claim with the wrong claimant or against the wrong defendant later than to attempt a substitution post-limitation.
3. Pleading “the claim”: the court’s narrow definition of “the claim” means that a broad-brush approach to pleading facts will not save a defective claim. If the facts required to establish liability against party A differ from those required for party B, then they are different claims for the purposes of CPR 19.6(3)(b).
4. No relief for “understandable” mistakes: the court has reaffirmed that section 35 of the Limitation Act 1980 is not a general discretion to do justice. Even if the mistake was understandable or “genuine”, if it falls outside the specific statutory gateways, the claim will be time-barred.