Duffy v Birmingham City Council: A Defective (Uncertified) Indemnity Certificate Does Not Invalidate a Bill of Costs or Detailed Assessment Commencement
Introduction
Duffy v Birmingham City Council [2026] EWCA Civ 146 is a Court of Appeal (Civil Division) decision addressing a recurring tactical issue in costs litigation:
whether a bill of costs is a nullity—and therefore ineffective to commence detailed assessment under CPR 47.6—where the bill is signed by a solicitor but does not also contain an
express certificate (via the “ticked box” in Precedent F) confirming compliance with the indemnity principle.
The claimant (a Council tenant) settled a disrepair claim by consent order requiring the Council to pay costs to be assessed if not agreed. The claimant served a notice of commencement and bill.
The Council did not serve points of dispute within 21 days, so the claimant obtained a default costs certificate.
The Council then sought to set aside the default certificate, ultimately advancing (on second appeal) the argument that the bill was invalid from the outset because it lacked the express indemnity certification.
Two procedural points framed the appeal: (i) whether the Council could raise a new pure point of law despite a concession below; and (ii) whether the defect made the bill invalid such that
the claimant was “not entitled” to a default costs certificate within CPR 47.12(1).
Summary of the Judgment
- The Court permitted the Council to withdraw its concession and argue the new legal point because it was a pure point of law and caused no uncompensable prejudice (applying Pittalis v Grant [1989] 1 QB 605).
- The appeal was dismissed: the claimant’s bill of costs, though defective in not ticking the express indemnity certificate box, was still valid and effective to commence detailed assessment under CPR 47.6.
- Accordingly, the claimant was entitled to the default costs certificate when the Council failed to serve points of dispute; the certificate was not liable to be set aside “as of right” under CPR 47.12(1).
- The Council retained the ability to pursue discretionary relief under CPR 47.12(2), but the Court expressed concern (without deciding merits) about proportionality and public-funds implications given the cost of repeated challenges.
Analysis
Precedents Cited
Pittalis v Grant [1989] 1 QB 605
This authority informed the Court’s procedural decision to allow the Council to advance a new point on appeal.
The Court treated the indemnity-certificate argument as a pure question of law and held that the claimant was adequately prepared and not prejudiced in a way that could not be compensated in costs.
The case thus supported flexibility where the appellate court can fairly and efficiently resolve a determinative legal issue.
Gundry v Sainsbury [1910] 1 KB 645
Cited as part of the lineage of the indemnity principle, Gundry anchors the core idea that party-and-party costs provide an indemnity rather than a “bonus.”
The Council relied on the “fundamental” character of this principle to argue that failure to certify it expressly should be treated as fatal.
The Court accepted the importance of the principle, but not the Council’s conclusion about nullity.
The Court referred to Sir Brian Neill’s summary of the indemnity principle, reinforcing that costs orders are not to overcompensate.
The significance in Duffy was contextual: it underscored why indemnity compliance matters, but it did not compel an outcome that every procedural omission connected to indemnity
automatically invalidates a bill.
The Council characterised Bailey as “seminal” support for the centrality of the indemnity certificate.
The Court of Appeal rejected that reading. Bailey was treated as establishing the opposite proposition:
because solicitors are officers of the court in a position of trust, their signature on the bill is itself treated as a certification that the bill is correct and does not offend the indemnity principle.
The judgment relied in particular on the passages where Henry LJ explained that the signature “is no empty formality” and that, absent suspicious circumstances, the court can assume indemnity compliance,
with disciplinary consequences for breach of that trust.
Gempride was used to confirm and modernise the Bailey trust-based approach:
when a solicitor signs a bill, they certify correctness (including hourly rates due from the client), and the court and paying party are entitled to rely on that certification unless there is reason for suspicion.
This was central to the Court’s conclusion that an additional, express “ticked-box” indemnity certificate is not conceptually necessary to make the bill operative—although it remains a mandatory requirement whose omission may be sanctionable.
Choudhury v Islam (Central London County Court, unreported 21 April 2021)
The Court endorsed HH Judge Lethem’s reasoning rejecting a “nullity” approach to defective bills of costs.
The key influence was the pragmatic and systemic critique: treating defects as invalidating commencement would reward indolence, invite ambush after long delay (even after enforcement),
and generate disproportionate consequences from minor slips.
Choudhury also framed points of dispute as the procedural vehicle for raising defects, and emphasised the curative role of CPR 3.10
(errors of procedure do not invalidate steps unless the court so orders).
Barking, Havering & Redbridge University Hospitals NHS Trust v AKC [2021] EWHC 2607 (QB) and [2022] Costs LR 1095
The Council argued these decisions undermined Choudhury.
The Court disagreed: in AKC the remedy was to strike out and require a replacement bill—an outcome Choudhury itself contemplated as a possible sanction.
Crucially, the Court distinguished between (i) striking out/ordering a replacement and (ii) declaring a bill invalid from inception.
The judgment relied on Newey LJ’s statement at [53] in the Court of Appeal decision: it is “very far” from the case that non-compliance should invariably result in strike-out,
“let alone treated as a nullity,” with lesser sanctions typically appropriate.
Legal Reasoning
(1) The “mandatory” nature of PD 47 certification does not equate to “nullity”
The Court accepted that PD 47 paragraph 5.21 is expressed in mandatory terms: the bill “must” contain appropriate certificates from Precedent F.
However, the Court rejected the leap from mandatory drafting to automatic invalidity.
A defective bill is still a bill; defects ordinarily attract case-management solutions or sanctions rather than retroactive invalidation.
(2) Signature-as-certification: the indemnity principle is already protected
The Council’s core submission—that indemnity certification is uniquely fundamental and therefore its omission uniquely fatal—was rejected because it conflicted with
the very authorities invoked.
Under Bailey v IBC Vehicles Ltd [1998] 2 Costs LR 46 and Gempride Ltd v Bamrah [2018] EWCA Civ 1367, a solicitor’s signature on the bill already operates as implicit certification,
grounded in the solicitor’s professional duty and disciplinary exposure.
On that footing, the Court reasoned that the absence of an express “ticked box” indemnity certificate cannot sensibly be elevated above other PD 47 defects so as to negate commencement.
Indeed, because the signature imports an implicit certification, the omission may be viewed as less serious than some other non-compliances.
(3) CPR 3.10 confirms a curative, non-nullity approach
The Court placed weight on CPR 3.10, which provides that an error of procedure does not invalidate a step in proceedings unless the court orders otherwise,
and empowers the court to remedy the error.
This reinforced that the proper response to a defective bill is generally correction, further information, targeted sanctions, or (in serious cases) strike-out—rather than treating the process as never having begun.
(4) Procedural discipline: points of dispute must still be served
The Court’s approach promotes procedural orderliness:
if the bill commences detailed assessment, the paying party must serve points of dispute within CPR 47.9.
A paying party cannot justify doing nothing by later asserting that a defect made the bill void, then seek mandatory set-aside of a default certificate under CPR 47.12(1).
Defects can be raised in points of dispute (and, where appropriate, by an application seeking directions, evidence, or strike-out).
Impact
- Nullity arguments narrowed: The decision strengthens the proposition that most defects in bills of costs—including omission of express Precedent F indemnity certification—are procedural irregularities, not jurisdictional failures to commence detailed assessment.
- Default costs certificates protected: Paying parties who miss the CPR 47.9 deadline cannot expect to set aside “as of right” under CPR 47.12(1) by identifying formal defects, unless those defects truly mean the receiving party was not entitled to the certificate.
- Greater reliance on CPR 3.10 and proportionate sanctions: The case encourages courts to cure or manage defects rather than invalidate steps retrospectively, aligning costs procedure with efficiency and proportionality.
- Reinforcement of solicitor trust model: The judgment restates and operationalises the Bailey/Gempride principle that the solicitor’s signature carries significant weight as a professional certification, with disciplinary consequences for abuse.
- Strategic behaviour discouraged: The Court’s endorsement of Choudhury signals hostility to “sit on hands” tactics and ambush nullity points after deadlines expire.
Complex Concepts Simplified
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Bill of costs: a detailed schedule of legal costs claimed by the successful/receiving party, used for assessment when costs are not agreed.
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Detailed assessment (CPR 47): the court process for deciding what costs are recoverable and in what amount.
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Indemnity principle: a receiving party cannot recover more from an opponent than the receiving party is liable to pay their own solicitor; costs are compensatory, not a profit-making “bonus.”
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Precedent F certificate: a prescribed set of “tick-box” certificates to include in a bill of costs under PD 47, including (where appropriate) a statement that the costs claimed do not exceed the client’s liability.
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Points of dispute (CPR 47.9): the paying party’s formal objections to items in the bill; must generally be served within 21 days.
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Default costs certificate (CPR 47.11): if the paying party fails to serve points of dispute in time, the receiving party may obtain a certificate effectively ordering payment of the claimed costs (subject to set-aside mechanisms).
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Set aside “as of right” vs discretion (CPR 47.12):
under 47.12(1) the court will set aside if the receiving party was not entitled to the certificate; under 47.12(2) the court may set aside for “some good reason” to allow assessment to continue.
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CPR 3.10: a general saving provision: procedural errors do not automatically invalidate steps; the court can remedy errors unless it orders otherwise.
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Nullity: a step treated as legally ineffective from the outset; the Court resisted expanding this category for bill defects.
Conclusion
Duffy v Birmingham City Council establishes that a bill of costs signed by a solicitor is not rendered invalid for the purposes of CPR 47.6
merely because the solicitor failed to tick the express Precedent F certificate confirming compliance with the indemnity principle.
The omission is a defect, not a nullity: it does not prevent commencement of detailed assessment, does not excuse failure to serve points of dispute,
and does not entitle a paying party to mandatory set-aside of a default costs certificate under CPR 47.12(1).
The decision consolidates a pragmatic, proportionate procedural approach: reliance on the solicitor’s signature-as-certification (per Bailey and Gempride),
remedial flexibility under CPR 3.10, and structured challenge through points of dispute rather than opportunistic nullity arguments.