ACL Netherlands B.V. (as successor to Autonomy Corporation Limited) & Ors v Michael Richard Lynch & Anor

After a trial, the court may admit further evidence where it is likely to assist in resolving the issues, despite the principles of finality and the ordinary expectation that parties present their whole case at trial.

The controlling inquiry is whether admission causes real forensic prejudice. If it does not, the court must also consider whether the further hearing would be disproportionate, having regard to costs and the interests of other court users. In complex quantum disputes, further evidence may be justified where liability findings create materially different variables and the evidence is needed to understand substantial differences between experts.

The judgment concerned the final quantum stage of substantial claims arising from the acquisition of Autonomy. Following the main judgment on liability and provisional conclusions on loss, the court permitted the parties to exchange extensive further expert evidence concerning revised accounts, valuation models and the effect of excluded transactions.

The claimants sought to restrict or exclude parts of the defendants’ post-judgment expert reports, arguing that the evidence reopened matters which should have been dealt with at trial. The defendants contended that the evidence fell within the assistance contemplated by the main judgment. The central issue was whether the disputed evidence should be excluded at the directions stage.

1. Application refused at this stage. The court declined to restrict or declare inadmissible parts of the expert evidence already exchanged. Final questions of prejudice, fairness and admissibility were left to the substantive quantum hearing.
2. The principles associated with finality and requiring parties to bring their whole case at trial were relevant, but the admission of further evidence after a long hearing remained a matter for judicial discretion under the overriding objective. The governing considerations were fairness, justice and proportionality.
3. The applicable test was whether the disputed evidence was likely to assist the court and, if so, whether admitting it caused real forensic prejudice to the claimants. If there was no such prejudice, the court had to consider whether any additional hearing would be disproportionate, having regard to costs and the interests of other court users.
4. The further reports were likely to assist the court in understanding a very substantial valuation gap between the experts. The complexity and interdependence of the liability findings, the need to recalibrate the true position, and the experts’ fundamentally different valuation approaches justified allowing the evidence to proceed for the present.
5. The ruling did not foreclose later exclusion of particular matters. The court expressly identified the new treatment of the Bank of America transactions as a point which might ultimately be held inadmissible, but considered it preferable to address that issue at the substantive hearing.
6. The experts were directed to discuss areas of agreement and disagreement. The matter was to be listed for a further hearing, provisionally with a five-day estimate and additional reading time.