Cahill v. Residential Tenancies Board – Re-affirming the “Entirely Successful” Rule on Costs and the Threshold for Remote-Hearing Complaints

1. Introduction

In Cahill v. Residential Tenancies Board ([2025] IEHC 446) the High Court, per Barniville P., delivered a post-judgment ruling that addresses the allocation of costs after the substantive appeal had already been dismissed for being out of time (Cahill (No. 1) [2025] IEHC 410).

The case involved:

Appellant – Jason Cahill, an unrepresented tenant appealing a determination order of the Residential Tenancies Board (“RTB”).
Respondent – The RTB, represented by solicitors and counsel.
Primary Issue in the present judgment – Whether the RTB, having been “entirely successful” on a preliminary objection that the appeal was lodged outside the 21-day statutory window, should receive its costs or whether alleged procedural disadvantages suffered by the appellant justified a departure from the ordinary rule on costs.

2. Summary of the Judgment

The Court confirmed its provisional view that the successful party is presumptively entitled to costs under s. 169 of the Legal Services Regulation Act 2015 (“LSRA 2015”) and re-cast Order 99 of the Rules of the Superior Courts. Finding no “special circumstances” to displace that rule—despite Mr Cahill’s complaints about remote-hearing difficulties—the Court ordered the appellant to pay the RTB’s costs of both the preliminary objection and the proceedings as a whole.

3. Analysis

3.1 Precedents Cited

Chubb European Group SE v. Health Insurance Authority [2020] IECA 183 – Recognised that an “entirely successful” party should ordinarily get its costs.
Higgins v. Irish Aviation Authority [2020] IECA 277 – Confirmed the same principle post-LSRA 2015.
Dunne v. Minister for the Environment [2008] 2 IR 775 – Earlier articulation of the “successful party” rule pre-LSRA, demonstrating the longevity of the principle.

Barniville P. applied those authorities to emphasise that the discretion under s. 168 and Order 99 remains structured by the presumption in s. 169(1). The judgment illustrates that, unless special factors are clearly present, costs follow the event.

3.2 Legal Reasoning

The reasoning unfolds in three logical steps:

Identify the Statutory Presumption – Section 169(1) LSRA 2015 states that a party “entirely successful” is entitled to costs unless the court orders otherwise.
Assess for “Special Circumstances” – The Court reviewed s. 169(1)(a)–(g) factors (e.g. conduct of the parties, particular nature of the case). Mr Cahill’s complaints did not correspond to any of these categories.
Examine Alleged Procedural Disadvantages – After listening to the Digital Audio Recording (DAR), the Court found that:

Mr Cahill successfully accessed and participated in the remote hearing;
He never raised real-time objections about audio issues;
He was granted full latitude to make submissions and introduce documents;
The contested documents were ultimately irrelevant to the timing point.

Accordingly, no basis existed to override the default rule on costs. Importantly, the judge re-affirmed that complaints aimed at the merits of the RTB determination—rather than the timing bar—could not be revived at the costs stage.

3.3 Impact

The decision is significant for three reasons:

Costs Doctrine Clarified – It provides a crisp post-LSRA 2015 restatement that a party who obtains dismissal on a preliminary objection is “entirely successful” for the purpose of costs—even where substantive merits are never reached.
Remote-Hearing Standards – The judgment sets a pragmatic threshold: minor technical difficulties or unraised real-time objections will not amount to “special circumstances” justifying a different costs outcome.
Guidance for Lay Litigants – While acknowledging Mr Cahill’s unrepresented status, the Court emphasised that latitude in procedure does not translate into immunity from adverse costs where statutory deadlines are missed.

4. Complex Concepts Simplified

Preliminary Objection – A challenge made at the start of proceedings that, if successful, ends the case without needing to examine the full merits (here, the objection was that the appeal was late).
“Entirely Successful” – Legal shorthand meaning a party has won on all issues that determine the outcome, even if on jurisdictional or procedural grounds.
Order 99 RSC – The part of the court rules dealing with costs. The 2020 “re-cast” version aligns with the LSRA 2015.
LSRA 2015 ss. 168–169 – Statutory framework giving courts discretion over costs but embedding a default that the winner pays none and the loser pays both sides, unless special circumstances exist.
Digital Audio Recording (DAR) – Official court audio which judges can consult to verify what transpired at a hearing.

5. Conclusion

Barniville P.’s costs ruling in Cahill v. RTB cements two intertwined principles: the robustness of the “entirely successful” presumptive entitlement to costs under the LSRA 2015, and the limited role that post-hearing complaints—especially about remote-hearing logistics—will play unless they are promptly raised and demonstrably prejudicial. Future litigants, particularly those self-represented, should note that:

Statutory time limits are strictly enforced;
If you lose solely on a preliminary point, you are still likely to face the full costs consequences;
Technical or procedural grievances must be aired immediately at the hearing; otherwise they will carry little weight at the costs stage.

Overall, the case provides clear guidance for courts and practitioners on costs allocation after procedural dismissals, and it helps to set expectations for virtual court participation in Ireland’s superior courts.