Court Affirms Importance of Expert Evidence in Patent Entitlement Dispute

Citation: [2024] EWHC 533 (Pat)
Judgment on


In the High Court of Justice Chancery Division Patents Court case between Dr Vanessa Hill and Touchlight Genetics Limited, key legal principles surrounding the use of scientific advisers (SAs) and expert witnesses in patent litigation were examined. This article provides an analysis of the 2024 judgment by Mr Justice Mellor and its implications for patent entitlement disputes within the field of biotechnology.

Key Facts

The case centered on a patent entitlement dispute involving synthetic DNA vector technology. Dr Hill claimed she retained ownership of certain inventions despite her prior assignment of related rights to Touchlight under a Service Agreement. The issue before the court was whether to appoint a SA, as argued by the Claimant, or to order the exchange of expert evidence, as contended by the Defendants.

The court had to consider the respective roles of SAs and expert witnesses, touching upon the fairness and transparency of proceedings, the adversarial process, and the adequacy of technical understanding required for the just resolution of the dispute.

The legal principles drawn upon in this case include:

  1. The court’s power to appoint a SA under s.70(3) of the Senior Courts Act 1981 and CPR r35.15.

  2. The duty to restrict expert evidence emphasized in CPR r35.1, where expert evidence should be “restricted to that which is reasonably required to resolve the proceedings.”

  3. Pre-established jurisprudence on the role of SAs, notably in Actavis Group PTC EHF v Actavis UK Ltd [2016] EWHC 1476 (Pat), determining that a SA does not decide the contentious issues in a case. Rather, their use is generally limited to providing non-controversial scientific background.

  4. The principle that fairness in proceedings necessitates the opportunity for adversarial challenge, including the right to call expert evidence and subject the opposing party’s evidence to scrutiny and cross-examination, as articulated in Halliburton Energy Services Inc v Smith International (North Sea) Ltd [2006] EWCA Civ 171.

The analysis of these core principles revealed that the appointment of a SA is not a substitute for expert evidence. Instead, it serves as an additional means to educate a Judge - particularly in technically complex proceedings where a Cat 4/5 Judge is presiding.


Justice Mellor determined that:

  1. An appointment of a SA without expert evidence would not sufficiently address technical issues in the case.

  2. Expert evidence was necessary to assist the court in understanding the technology and inventive concepts in dispute.

  3. Permission would be granted to each party to call one technical expert witness in molecular biology to address technical aspects arising in connection with specific identified issues from the agreed list.

  4. A structured discussion between experts was mandated to narrow down disputed technical issues and to draft a joint statement outlining points of agreement and disagreement.

Justice Mellor’s directives ensured the expert evidence would complement the role of a potential SA, enhancing the court’s technical understanding while preserving the adversarial nature of proceedings.


The Dr Vanessa Hill v Touchlight Genetics Limited case reinforces the principle that expert evidence is crucial in patent litigation involving technical disputes. It ensures fairness and transparency, upholding an adversary system where evidence can be tested through cross-examination. The allowance for expert evidence, supported by a directive to identify areas of consensus, reflects a balanced approach aimed at aiding the court’s comprehension of technical matters without undermining the adversarial process. Justice Mellor’s decision provides clarity on the appropriateness of implementing SAs and expert witnesses in complex patent disputes within the UK judiciary.

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