Attersley v UK Insurance: fixed costs apply to late Part 36 acceptance in ex-Protocol claims

Late acceptance of a Part 36 offer in an ex-Protocol claim does not entitle a claimant to standard basis costs, even where the case has since been allocated to the multi-track.
The Court of Appeal has allowed the defendant's appeal in Laura Attersley v UK Insurance Limited [2026] EWCA Civ 217, holding that rule 36.20, rather than rule 36.13, governs the costs consequences where a claimant accepts a Part 36 offer out of time in a claim that originated under the RTA Protocol.
The claimant was injured in a road traffic accident in March 2018. Her claim entered the RTA Protocol before exiting it following a liability dispute. A Part 7 claim form was subsequently issued in February 2021, by which time the anticipated value had risen substantially to around £150,000. The defendant made a Part 36 offer of £45,000 in March 2021, which the claimant did not accept within the 21-day relevant period. The case was allocated to the multi-track at a CMC in January 2022. In July 2022, following an application to amend the defence to allege fundamental dishonesty, the claimant accepted the outstanding offer.
The central question was whether the costs consequences of that late acceptance fell to be determined by rule 36.13 — which provides for standard basis costs where costs are not fixed — or by rule 36.20, which applies specifically to ex-Protocol claims and provides for fixed recoverable costs.
At first instance, HHJ Duddridge held that rule 36.20 applied and restricted the claimant to fixed costs. Stacey J allowed the claimant's appeal, reasoning that the decision in Qader v Esure Services Ltd [2016] EWCA Civ 1109 had the effect of completely disapplying the fixed costs regime in Section IIIA of Part 45 upon allocation to the multi-track, so that rule 36.13 governed instead.
The Court of Appeal (Miles, Falk and Lewison LJJ) disagreed. Miles LJ, giving the leading judgement, held that rule 36.13 is expressly subject to rule 36.20, and that the correct starting point is to ask whether rule 36.20 applies at all — not to begin with the sub-rules of rule 36.13. Since the claim fell within Section IIIA of Part 45 at the date the relevant period expired, rule 36.20 plainly applied. The subsequent allocation to the multi-track did not change that analysis.
The court rejected the submission that Qader established a blanket retrospective disapplication of the fixed costs regime. Qader was concerned solely with whether a multi-track case should be subject to fixed costs or costs management; it did not address the interplay between Part 45 and Part 36, and did not decide that allocation to the multi-track erases the history of a claim's earlier status under the fixed costs regime. The phrase "and for so long as the case is not allocated to the multi-track" in rule 45.29B operates prospectively, not retrospectively for all purposes.
Miles LJ emphasised that reading the claimant's construction into the rules would introduce precisely the kind of uncertainty that Qader itself had sought to avoid, and would produce anomalous results: a claimant who accepts a Part 36 offer out of time would, on that reading, obtain a windfall in the form of standard basis costs that she would not have received had she accepted the offer promptly. That outcome sits uneasily with the underlying purpose of Part 36, which is to encourage early settlement by anchoring costs liability to the costs environment at the date the relevant period expired.
Where, as here, the relevant period expired while the claim remained within the fixed costs regime, the claimant's entitlement is limited to fixed recoverable costs under rule 36.20 regardless of any later allocation to the multi-track.
The court noted, by way of footnote, that the rules do not yield straightforward answers in scenarios where a Part 36 offer is made after allocation to the multi-track, or where the relevant period straddles allocation, and invited the Rules Committee to consider clarification.
