The Engagement-Duty Costs Rule: P.K. v V.O.S. & Anor and the Proportional Reduction of Costs for Inadequate Pre-Litigation Engagement

1. Introduction

P.K. v V.O.S. & Anor ([2025] IEHC 354) is a High Court ruling confined to the issue of costs following the substantive judgment of 28 April 2025 ([2025] IEHC 244). The Applicant (P.K.) had successfully secured an order of certiorari quashing a decision of the National Transport Authority (“Licensing Authority”) refusing him a Small Public Service Vehicle (SPSV) licence. However, the Respondents—the Licensing Authority (V.O.S.) and the Commissioner of An Garda Síochána—contested liability for costs.

Ms. Justice Siobhán Phelan’s costs decision lays down a refined approach to the “costs follow the event” principle under the Legal Services Regulation Act 2015 (LSRA 2015). Most notably, the Court emphasised that:

a successful party who fails on the “fundamental premise” of the action is not “entirely successful”, and
failure to engage properly with an administrative decision-maker pre-litigation constitutes misconduct sufficient to warrant a proportional reduction of costs – even if it is not “egregious” in the Mahon v Keena sense.

2. Summary of the Judgment

After weighing submissions from both parties, the Court ordered:

P.K. is to recover 50 % of the costs of the judicial-review proceedings (including reserved costs), subject to taxation if not agreed.
The licensing application is remitted for fresh consideration by a different decision-maker (confirming an agreement reached by the parties).

Key points underpinning the 50 % order:

P.K. won relief (certiorari) but lost on the core legal contention that the Licensing Authority could not rely on the fact of an allegation after an acquittal.
The action was a one-day hearing in which P.K. did succeed on subsidiary grounds (inadequate pleadings, procedural unfairness, inadequacy of statutory appeal), favouring a costs award.
Nevertheless, P.K.’s “lack of proper engagement” with the Authority— a failure to seek disclosure, provide transcripts, or correspond constructively— was criticised by the Court as having contributed to the flawed administrative outcome and made litigation more likely.
That conduct, though not “flagrantly unlawful”, was serious enough to warrant a penalty in costs, leading to the 50 % reduction.

3. Analysis

3.1 Precedents Cited and Their Influence

Legal Services Regulation Act 2015 • Section 168(2)(d): recognises costs orders in favour of “partially successful” parties. • Section 169(1)&(1)(a): presumes costs follow the event but permits departure where the successful party’s conduct—before or during proceedings—justifies it.
Veolia Water UK PLC v Fingal County Council ([2006] IEHC 137) Referenced generally for the principle that a party need not succeed on every ground to recover costs, unless the additional grounds materially prolong proceedings. P.K. relied on this to argue for full costs.
Chubb European Group SE v Health Insurance Authority ([2020] IECA 183) Clarified that the “conduct” factor in s.169(1)(a) is not a mechanism to police regulatory compliance; nevertheless, it remains available where a party’s behaviour contributes to proceedings.
Mahon v Keena ([2009] IESC 78, [2010] 1 I.R. 336) The Supreme Court’s reference point for “egregious conduct” justifying the denial of costs to a successful party (destruction of documents in that case). P.K. cited this to say his conduct fell short of that threshold. Justice Phelan distinguished Mahon, ruling that s.169(1) allows for less egregious, yet still significant, misconduct to attract cost consequences.

3.2 The Court’s Legal Reasoning

The reasoning followed a structured path:

Identify the degree of success – P.K. was not “entirely successful”. Section 168 recognises that when success is only partial, the usual rule (costs follow the event) loses automatic primacy.
Assess the impact of conduct – The Court treated the Applicant’s pre-litigation behaviour as a significant factor under s.169(1)(a) and the inherent discretion. – Failures: abrasive tone, no request for materials, no provision of transcripts, no constructive dialogue.
Weigh proportionality – A complete denial of costs would over-penalise the Applicant given his relief. – A token deduction would inadequately reflect the Court’s disapproval and deterrence considerations. – A “mid-point” 50 % reduction struck the right balance.
Articulate a prospective rationale – The judgment emphasises scarce court resources and the public law context: judicial review should be a last resort after genuine administrative engagement.

3.3 Potential Impact of the Decision

The ruling is likely to reverberate in several ways:

Costs calculus in judicial review: Practitioners must now factor in that even moderate missteps in pre-decision engagement may lead to substantial costs reductions, not merely token findings.
Administrative law practice: Applicants (and their solicitors) are put on clear notice that they must exhaust reasonable dialogue with regulators—requesting materials, clarifying concerns, and supplying relevant documents—before seeking certiorari.
Clarification of “conduct” threshold: The decision narrows the gap between the “egregious” misconduct bar in Mahon and the more routine failings contemplated under s.169 LSRA. It confirms that “egregious” is not the mandatory baseline for adverse cost consequences.
Partial success doctrine refined: Where an applicant’s core argument fails, but relief is nevertheless granted on ancillary grounds, courts may calibrate costs proportionately rather than adopting an ‘all-or-nothing’ model.

4. Complex Concepts Simplified

Certiorari: A prerogative (now “supervisory”) order quashing a decision of a public body where that decision is unlawful.
Costs follow the event: The traditional rule that the losing party pays the winner’s legal costs.
Partial success: A situation where a party wins some but not all issues; s.168 LSRA empowers the court to apportion costs accordingly.
Pre-litigation engagement: Correspondence and cooperation between an applicant and a decision-maker aimed at resolving or narrowing disputes before initiating court proceedings.
Conduct grounds (s.169(1)(a)): A statutory basis to adjust costs where a party’s behaviour before or during the case merits reward or sanction.

5. Conclusion

P.K. v V.O.S. & Anor introduces a nuanced “engagement-duty costs rule”: a successful litigant who secures relief can nevertheless face a meaningful reduction in recoverable costs where (a) they failed on the fundamental premise of their claim, and/or (b) their poor engagement helped precipitate the litigation. The case recalibrates Irish costs jurisprudence post-LSRA 2015 by lowering the threshold at which misconduct influences costs—below the “egregious” bar set by Mahon v Keena—and by promoting proportionality in partial-success scenarios.

Future judicial-review practitioners must treat comprehensive, constructive engagement with decision-makers as an essential strategic step; failure to do so may now carry a quantifiable price—literally, half the bill.