Part 36.20 Fixes Costs by Reference to the Expiry of the Relevant Period, Not Later Multi-Track Allocation
1. Introduction
Attersley v UK Insurance Ltd ([2026] EWCA Civ 217, CA (Civ Div), 4 March 2026) addresses a recurring costs problem in
ex-Protocol personal injury litigation: where a claimant begins under the RTA Protocol, exits it, later issues Part 7 proceedings, and then
accepts a defendant’s Part 36 offer after the offer’s 21-day “relevant period”.
The critical factual wrinkle was timing. When the relevant period expired, the claim had not yet been allocated to track; by the time the claimant
eventually accepted the offer, the claim had been allocated to the multi-track. The issue was whether the claimant’s recoverable
costs were (i) fixed recoverable costs under CPR Part 45, Section IIIA via CPR 36.20, or (ii) standard basis
costs under CPR 36.13.
The parties were:
- Claimant: Ms Attersley (RTA claimant; claim revalued well above the Protocol’s low value assumptions).
- Defendant: UK Insurance Ltd (insurer for the at-fault driver; admitted liability; made a Part 36 offer of £45,000).
Procedural background (key milestones)
- Claim started under the RTA Protocol; exited on liability dispute.
- Part 7 issued near limitation with pleaded value up to £150,000 and multiple expert disciplines.
- Defendant made a Part 36 offer (£45,000). Not accepted within 21 days.
- Case later allocated to the multi-track, with extensive expert evidence and costs management.
- Claimant accepted the Part 36 offer late; dispute arose about which costs regime governed.
2. Summary of the Judgment
The Court of Appeal allowed the defendant’s appeal and restored HHJ Duddridge’s order. It held that:
- CPR 36.20 governed the costs consequences of late acceptance of the defendant’s Part 36 offer.
- The claimant’s entitlement was therefore to fixed costs by reference to the stage applicable at the date the relevant period expired
(i.e. while the claim was still within Section IIIA’s scope), even though the claim was later allocated to the multi-track.
- Qader did not require treating multi-track allocation as retrospectively removing the claim from fixed costs “for all purposes”.
- It was unnecessary to decide the defendant’s alternative reliance on Williams.
3. Analysis
3.1 Precedents Cited
Role in this case: Qader was the claimant’s main authority for the proposition that, once allocated to the multi-track, Section IIIA fixed costs
“ceased to apply”, so that late acceptance should fall under CPR 36.13 (standard basis) rather than CPR 36.20.
What Qader decided (as characterised by the Court of Appeal here): Qader was about whether fixed costs should apply to claims that
had been allocated to the multi-track. The Court of Appeal in Qader corrected a drafting error (using Inco Europe v First Choice Distribution [2000] 1 WLR 586)
by effectively reading into rule 45.29B the limitation “and for so long as the claim is not allocated to the multi-track”, reflecting the legislative intention that
multi-track cases should not be confined to fixed costs.
How it influenced (and was limited in) Attersley: The Court of Appeal treated Qader as addressing the applicability of Part 45
to costs in multi-track cases, not the distinct question of how Part 36 “locks in” costs consequences by reference to the expiry of the relevant period.
Attersley held Qader does not establish a broad, retrospective rule that allocation to multi-track causes the case to be treated as if it had
never been within Section IIIA for other procedural purposes (notably Part 36).
Inco Europe v First Choice Distribution [2000] 1 WLR 586
Role: Cited to explain the interpretive technique used in Qader (judicial correction of drafting error to give effect to clear legislative intention).
Attersley relied on this history to show Qader’s correction was targeted: it ensured multi-track cases were not governed by fixed costs going forward, but did not mandate
retrospective re-characterisation for every procedural interaction.
Role: Cited for the nature of Part 36 as a “carefully structured and highly prescriptive” code in which certainty is a key value.
This supported the court’s preference for an interpretation that allows parties to identify costs consequences by reference to a clear temporal anchor
(the expiry of the relevant period), rather than later, contingent procedural events (track allocation).
Matthews v Metal Improvements Co Inc [2007] EWCA Civ 215; [2007] C.P. Rep 27
Role: Cited for the purpose of Part 36: encouraging early settlement by shifting the costs risk onto an offeree when a reasonable offer is made early.
This purposive context underpinned the court’s view that a claimant should not be in a better costs position by accepting late.
Role: Reinforced the “carrot and stick” account of Part 36. Attersley used this to justify an interpretation that preserves the intended incentive
structure: delay should not confer a costs windfall where the offer was capable of acceptance within the relevant period.
Role: Used to support the interpretive principle that where there is tension between a general and a specific rule, the specific rule prevails.
The court reasoned that even if one perceived friction between Part 45’s general fixed-costs architecture and Part 36.20’s specific settlement-costs provision,
rule 36.20 is the more specific instruction and should govern.
Ho v Adelekun (No. 1) [2019] EWCA Civ 1988; [2019] Costs LR 1963
Role: Cited (para 33) for the proposition that it is “more natural” to read the cessation of fixed costs on transfer to multi-track as operating
prospectively, not retrospectively “in relation to the past costs”. This was deployed to rebut the claimant’s attempt to treat allocation as wiping out
Section IIIA’s prior relevance for the Part 36.20 inquiry.
Role: Raised as the defendant’s alternative case: if fixed costs did not apply directly, the court should assess costs at an equivalent level
(a form of indirect “cap”). The Court of Appeal found it unnecessary to decide this, having held rule 36.20 applied directly. The judgment nonetheless preserves the
conceptual boundary noted by Stacey J: Williams concerned costs consequences flowing from unreasonable procedural conduct (in that context, pre-action protocol compliance),
not a general licence to “import” fixed costs by analogy.
3.2 Legal Reasoning
(a) The structural relationship between CPR 36.13 and CPR 36.20
The court’s reasoning begins with the internal architecture of Part 36:
- CPR 36.13 (general costs consequences of acceptance) is expressly stated to be “subject to” CPR 36.20.
- Therefore, the first question is not “are costs fixed under 36.13(3)?” but rather “does 36.20 apply?” If yes, 36.13 yields.
(b) When does CPR 36.20 apply? The key temporal anchor
CPR 36.20 applies where Section IIIA applies (via CPR 45.29A(1)), i.e. to claims started under the RTA Protocol that no longer continue under it. This was common ground.
The decisive interpretive move was the court’s insistence on the date that matters under CPR 36.20(4):
- Where a Part 36 offer is accepted after the relevant period, CPR 36.20(4)(a) entitles the claimant to fixed costs for the stage applicable at the
date the relevant period expired.
- If, at that expiry date, the claim had not yet been allocated to multi-track, then Section IIIA fixed costs were still “in play” and can be applied without difficulty.
On the facts, the claim was within Section IIIA at relevant-period expiry, so CPR 36.20(4) operated in its straightforward, textually explicit manner.
(c) Rejecting “retroactive disapplication” by later multi-track allocation
Stacey J’s approach treated multi-track allocation as removing the claim from Section IIIA in a way that displaced CPR 36.20 and reinstated CPR 36.13.
The Court of Appeal rejected this because:
- The words “for so long as the case is not allocated to the multi-track” in CPR 45.29B are naturally temporal and do not imply
retrospective erasure of Section IIIA’s earlier applicability.
- Qader was not a Part 36 case; it did not consider the interplay with Part 36 or require retrospective treatment “for all purposes”.
- Reading allocation as retrospectively altering the Part 36 costs consequences would introduce uncertainty and undermine the settlement incentives of Part 36.
(d) Purposive coherence: avoiding a “late acceptance windfall”
The court’s construction aligned text with purpose:
- If acceptance within time yields only fixed costs, it is “surprising” if accepting late yields a larger, standard-basis recovery purely because allocation happened later.
- Part 36 is intended to shift costs risk and reward prompt, informed decision-making within the relevant period.
- The defendant’s choice not to withdraw the offer did not justify shifting the costs regime; maintaining the offer can rationally be understood as
maintaining the settlement opportunity while anchoring costs consequences to the relevant-period expiry environment.
(e) Specific-over-general (if conflict were assumed)
Although the court held there was no true conflict, it added that if there were tension between Part 45 and Part 36.20, the specific settlement-costs
machinery in CPR 36.20 would prevail over the more general fixed-costs provisions in Part 45 (per Solomon).
3.3 Impact
(a) Practical rule for litigators and costs judges
The decision establishes a clear operational rule for late acceptance in ex-Protocol cases:
- Where the relevant period expires while the claim is still within Section IIIA (i.e. before multi-track allocation),
CPR 36.20 governs and fixed costs are recoverable by reference to the stage at relevant-period expiry.
- Later allocation to the multi-track does not convert the claimant’s entitlement into standard basis costs for the purposes of that Part 36 acceptance.
(b) Incentives and settlement behaviour
Attersley reduces the scope for strategic behaviour or accidental windfalls whereby a party obtains a higher costs regime by waiting for later case-management events.
It also enhances predictability for defendants making Part 36 offers in ex-Protocol claims: the “cap” is more reliably pegged to the relevant-period expiry.
(c) Relationship with QOCS
The case sits against the background that, in personal injury claims, the default rule that a late-accepting claimant pays the defendant’s post-relevant-period costs
may be practically unenforceable due to Qualified One-Way Costs Shifting (as it then stood). By affirming fixed costs on the claimant’s side,
Attersley limits the asymmetry created when the defendant’s reciprocal costs entitlement is constrained in practice by QOCS.
(d) Identified “gaps” and future clarification
Importantly, the court flagged (without deciding) harder scenarios where:
- a Part 36 offer is made after multi-track allocation in an ex-Protocol claim; or
- the offer is made before allocation but the relevant period expires after allocation.
The court suggested the Rules Committee may wish to clarify these, noting the present drafting may not yield straightforward answers where Section IIIA tables
are not “applicable” at the acceptance date because fixed costs are disapplied by allocation.
4. Complex Concepts Simplified
-
RTA Protocol / “ex-Protocol” claim: A streamlined pre-action process for low-value road traffic PI claims. A claim may “exit” the Protocol (e.g. liability dispute)
and then proceed under Part 7. Such claims can still attract a fixed recoverable costs regime in Part 45, Section IIIA, subject to allocation.
-
Part 36 offer and “relevant period”: A formal settlement offer with defined costs consequences. The “relevant period” is usually 21 days; acceptance within it
carries one costs outcome, while acceptance after it carries another.
-
Fixed recoverable costs vs standard basis costs: Fixed costs are predetermined amounts (tables) largely independent of actual work done. Standard basis costs are
assessed for reasonableness and proportionality (often producing higher recoveries in complex, multi-track litigation).
-
Track allocation (fast track / multi-track): The court assigns a case-management “track” based on value/complexity. Multi-track cases usually involve more steps,
experts, and costs management.
-
QOCS (Qualified One-Way Costs Shifting): In many PI claims, defendants’ costs orders against claimants are restricted in enforcement (subject to exceptions),
which can affect the practical balance of Part 36’s “stick”.
-
“Subject to” in drafting: When a rule says it is “subject to” another, the latter takes priority if it applies. Attersley treats this as decisive in the
ordering of the analysis between CPR 36.13 and CPR 36.20.
5. Conclusion
Attersley v UK Insurance Ltd establishes that in ex-RTA Protocol claims, the costs consequences of late acceptance of a defendant’s Part 36 offer
are governed by CPR 36.20 where, at the time the relevant period expired, the claim was still within Section IIIA’s fixed costs regime.
Subsequent allocation to the multi-track does not retrospectively disapply Section IIIA “for all purposes” so as to move the case into CPR 36.13
and standard basis costs.
The judgment reinforces Part 36’s policy of certainty and early settlement incentives, confines Qader to its proper domain, and provides a clear temporal anchor
for determining recoverable costs—while expressly inviting future rule clarification for scenarios where multi-track allocation occurs earlier in the Part 36 timeline.