Citadel Securities (Europe) Ltd v GSA Capital Partners LLP & Ors

The management of complex commercial litigation requires a pragmatic application of the overriding objective. Sampling is inappropriate where it creates artificial limits on evidence, risks unfairness, or prevents the court from evaluating the case as a whole. A split trial is likewise unsuitable where findings on liability directly affect valuation and remedy.

Requests for further information must be reasonably necessary and proportionate. In breach of confidence claims, particularity is important, but the required detail depends on the circumstances and may extend beyond identifying the alleged confidential information. Confidentiality restrictions must protect trade secrets while preserving a party’s effective participation in the litigation.

The claimant alleged that former personnel disclosed confidential algorithmic trading information to the defendants during recruitment discussions. It brought claims including breach of confidence, procuring breach of confidence, dishonest assistance, unlawful means conspiracy and related financial and injunctive claims.

The hearing concerned case management rather than the merits. The court considered sampling, trial bifurcation, requests for further information, the terms of a confidentiality protocol, costs budgeting and trial directions. The central questions were whether the proposed procedures were fair, proportionate and consistent with the overriding objective.

1. Sampling. The application to determine liability and remedy by reference to selected lines of disputed documents was refused. The evidence was technically complex, but the trial was unlikely to require line-by-line adjudication. Sampling would create artificial disputes about related questions, restrict the defendants’ ability to rely on the general or public nature of information, and risk unfairness in issues concerning knowledge, intention, use and credibility. The claimant could instead narrow its positive case.
2. Split trial. The application for separate liability and quantum trials was refused. The approach to splitting trials is pragmatic and must serve the overriding objective, taking account of costs, duplication, delay, settlement, witness burden, judicial resources, appeal risks and prejudice. Here, findings about the nature, confidentiality and value of information would directly affect the assessment of negotiating and moral damages. A second hearing created substantial risks of duplicated evidence, incomplete findings and a bifurcated appeal.
3. Further information. Requests under CPR Practice Direction 18 had to be reasonably necessary and proportionate. The claimant was required to identify, by disclosure, the source information said to have been copied or derived, because this was needed to process disclosure and understand the case. Further parsing of documents and detailed information about what the documents themselves said was unnecessary. Allegations that affidavits were false or inaccurate had to identify the relevant paragraphs and briefly explain the basis, particularly given the potential reputational consequences.
4. Breach of confidence pleading. The particularity principles in John Zinc Company v Wilkinson and Ocular Sciences Limited v Aspect Vision Care Limited were treated as applications of the general proportionality test, rather than exhaustive rules preventing any further particulars in every case.
5. Confidentiality protocol. Restrictions on expert access were justified where there was a real risk of inadvertent misuse or disclosure. The court balanced the importance and sensitivity of the information, the need for technical expertise, practical disruption and the parties’ ability to know and meet the case. Secure work at a solicitor’s office was required for the defendants’ expert. His notification undertaking was limited to two years. Additional contractual undertakings were refused as unnecessary and potentially chilling, since the court undertakings were detailed and supported by the possibility of criminal sanction.
6. The protocol was to be finalised, and revised costs budgets and agreed trial directions were to be submitted for approval.