The Ryanair v. Skyscanner Discovery Precedent: Embedding Proportionality, Sampling, and Temporal Reach in High-Tech Competition Litigation

1. Introduction

The High Court’s judgment in Ryanair DAC v. Skyscanner Ltd & Ors ([2025] IEHC 320) tackles an increasingly common procedural battleground in modern commercial disputes: discovery in data-heavy, multi-faceted litigation that mixes intellectual-property (IP) claims with competition-law counterclaims. Ryanair, alleging “screen scraping”, trade-mark misuse and other torts, sought 28 discovery categories. Skyscanner, defending and counter-claiming for abuse of dominance under Art. 102 TFEU, sought 17. After four hearing days and extensive correspondence, Sanfey J. delivered a granular ruling that crystallises three guiding principles:

Proportionality – discovery must balance evidential utility with the burden imposed;
Sampling – representative document sets can substitute for voluminous production;
Temporal Reach – a default five-year (pre-COVID) window, extendable where market-power analysis demands continuity.

These principles now constitute a persuasive blueprint for discovery in complex technology-driven litigation before the Irish Commercial Court.

2. Summary of the Judgment

Sanfey J. attached two negotiated charts to his ruling, then systematically pronounced on every outstanding category. Key determinations include:

Licence & source-code discovery: Ordered, but limited to “documents sufficient to show” the contested processes, curtailing wide “all documents” requests.
Sampling: For OTA-related technical data, discovery confined to a sample of five OTAs and five Ryanair flights, echoing Ryanair v. Vola.ro [2021] IEHC 788.
Temporal windows: Competition-law categories generally reach back to 1 January 2015 and up to the present, securing a continuous five-year pre-pandemic benchmark.
Executive-management limitation: “All documents” trimmed to records held or seen by Ryanair’s executive management, reflecting proportionality.
Confidentiality safeguards: Redaction permitted for commercially sensitive third-party contracts, but only where context remains intelligible.
Refusals: Vague or speculative categories (e.g., generic “unfavourable commentary”, expansive searches for every “Ryanair” reference) were refused.

Skyscanner succeeded in compelling production of market-share spreadsheets, pricing and capacity data, while Ryanair secured limited source-code and GitHub materials. Both parties obtained competing datasets for their antitrust experts.

3. Analysis

3.1 Precedents Cited

Compagnie Financière du Pacifique v. Peruvian Guano (1882) 11 QBD 55 – classic relevance test.
Framus Ltd v. CRH plc [2004] IESC 25 – proportionality in discovery.
Tobin v. Minister for Defence [2020] 1 IR 211 – reaffirmed necessity/proportionality.
Ryanair v. SC Vola.ro [2021] IEHC 788 – sampling endorsed; relied upon here.
Ryanair v. Aer Rianta [2003] 4 IR 264 – relevance threshold cited.
EU Commission Guidance 2009/C 45/02 – dominance analytical framework, informing categories 14-17.
Earlier interlocutory rulings in this litigation: [2020] IEHC 399/584; [2022] IEHC 696; [2022] IECA 64.

Sanfey J. synthesised these authorities, stressing that discovery must not become a burdensome expedition (“Peruvian Guano plus proportionality”).

3.2 Court’s Legal Reasoning

Necessity & Proportionality. The judge repeatedly balanced the “litigious advantage” against the production burden, citing Tobin. Categories that merely “could” assist were trimmed or refused if disproportionate.

Sampling Doctrine. Borrowing from his own judgment in Vola.ro, the Court affirmed that where systems generate millions of records (here, 300 OTAs and 100 m monthly users), a statistically meaningful sample suffices to test the pleaded process.

Temporal Scope. For dominance analysis the Court deemed a minimum five-year continuous dataset indispensable, unaffected by COVID-19 turbulence. This start-date (1 Jan 2015) now stands as a benchmark for competition discovery unless specific burden evidence is supplied.

Executive-Management Filter. To stop “boil-the-ocean” searches, many categories were limited to documents held, seen or created by executive management—individuals most likely to possess policy-level materials probative of abuse of dominance.

“Documents sufficient to show”. For source-code and technical architecture the Court used this phrase to avoid wholesale repository dumps while still capturing explanatory evidence.

Discovery & Counterclaim Logic. Since Skyscanner bears the onus on its Art. 102 counterclaim, it merited discovery to test market definition, dominance and anticompetitive effects. Conversely, Ryanair’s IP claims required discovery confined to pleaded works.

3.3 Likely Impact

Guidance for Digital-Platform Litigation – The judgment sets out a step-by-step template for dealing with overlapping IP and competition requests.
Standardising Sampling – Courts (and litigants) can cite this case when substituting representative datasets for unwieldy totals.
Five-Year Rule of Thumb – Parties should anticipate producing at least five years’ market data where dominance is alleged, barring exceptional burden evidence.
Executive-Management Limitation – Expect future orders to confine broad “all documents” demands to high-level custodians unless technical detail is indispensable.
Intersection of IP & Antitrust – The ruling illustrates how discovery for anti-competitive conduct can reach into IP enforcement strategies (e.g., Ryanair’s “Shield” technology) yet remain bounded by necessity.

4. Complex Concepts Simplified

Screen Scraping: automated bots extract data from a website without using the official API.
PFT Data: “Price, Flight & Time” information—core schedule and fare data.
Meta-Search Site: a site (e.g., Skyscanner) that compares flight offers across airlines/OTAs but may redirect users elsewhere to book.
OTA (Online Travel Agent): websites that resell or package airline inventory (e.g., eDreams, Lastminute) and usually complete the booking themselves.
dBook: Skyscanner’s embedded booking interface allowing completion inside the Skyscanner environment.
O&D City/Route Pair: The point-of-origin/point-of-destination pair used by competition authorities to define airline markets (e.g., DUB-STN).
Article 102 TFEU: EU Treaty provision prohibiting abuse of a dominant market position.

5. Conclusion

Ryanair v. Skyscanner offers a master-class in calibrating discovery demands in sprawling tech-sector litigation. Sanfey J. reaffirmed classical relevance tests but updated them for the digital era—insisting on tight proportionality, endorsing sampling and mandating a pragmatic temporal window. By intertwining IP and competition considerations, the Court has provided future litigants with a practical roadmap: articulate clear pleadings, justify each category, and prepare to compromise through tailored sampling or executive-custodian limits. The decision will resonate beyond Irish borders as common-law courts grapple with massive datasets and hybrid legal claims.