Patents: guidance on experiments and scientific advisers

By Audrey Horton


The High Court has provided guidance on use of evidence based on computer modelling, court scientific advisers and the scope of cross-examination of a witness about a Civil Evidence Act 1995 (1995 Act) notice to admit hearsay evidence.


A party seeking to prove any fact by using experiments as evidence must serve on all parties a notice: stating the facts which the party seeks to establish; and giving full particulars of the experiments proposed to establish them (paragraph 7.1, Practice Direction 63).

A scientific adviser may be appointed to assist the Patents Court (section 70(3), Senior Courts Act 1981) (section 70(3)). The assessor will assist the court in dealing with a matter in which the assessor has skill and experience (Civil Procedure Rule (CPR) 35.15(2)) (CPR 35.15). Although CPR 35.15 only uses the word "assessor", the Court of Appeal has held that this rule also included scientific advisers (Halliburton v Smith [2006] RPC 2).

A party proposing to adduce hearsay evidence must give notice to the other party  and, on request, particulars of the evidence as is reasonable and practicable in the circumstances to enable that party to deal with any matters arising from its being hearsay (section 2(1), 1995 Act). Where a party proposes to rely on hearsay evidence, the court may, on request, require that party to call the maker of the statement to be cross-examined (CPR 33.4).


E issued proceedings against P for patent infringement. The High Court held that E did not have to serve a further pleading giving particulars of the alleged infringement because its construction of the patent could be discerned from correspondence. 

E then wrote to P indicating a change of stance on its case as to construction (the letter). 

P applied for further information in relation to E’s use of experimental proof, the appointment of a court scientific adviser, and permission to call and cross-examine the maker of a statement about a 1995 Act notice. P argued that the letter meant that E’s position needed to be clarified by requiring E to answer certain questions, and that these answers should be formally recorded in a pleading.


The court granted the application in part. It also gave general guidance in relation to the use of computer simulations as experimental evidence. 

In conventional scientific experiments in a patent case it is usual to have directions for a witnessed repeat of the experiment. In some cases a repeat might be disproportionate but the availability of a witnessed repeat was important. The same applied to computer modelling, but the need to have a witnessed repeat might be removed by providing the totality of the input data and the computer software to the other party so that they could run the model themselves and see whether the result was genuine.

It was necessary for E to explain what the experiments were supposed to prove and what role they were to play in the case. Proper notice had to be given to P of what facts the experiment was supposed to prove. If E changed its case and wished to rely on the same experiment to prove something different, permission to amend the Notice of Experiments was required.

General guidance was also given on whether the court should sit with a scientific adviser. Where a case involves a difficult area of science, the correct approach is for the parties to arrange for the judge hearing the trial to have a non-controversial introductory course, probably over no more than a day, before reading into the case. With that assistance a Category 4/5 judge (with a technical background and patent law experience) would then be able to handle the trial itself without a scientific adviser sitting in the trial, but assisted by the technical primer, the expert witnesses and the parties’ legal teams. Any written materials produced by the scientific adviser for the judge should be given to the parties after the introductory course had taken place. If they wished to comment, they could do so at trial. Verbal discussions between the scientific adviser and the judge would not be available but a reasonable and fair minded observer would understand the respective roles of the court and the scientific adviser and would have no reason to think that these roles had not been fulfilled.

Cross-examination under CPR 33.4 was limited to the contents of the hearsay statement and did not extend more widely. The party cross-examining already had the equivalent of the evidence in the form of the hearsay statement. If the cross-examining party could cross-examine more widely, they would be able to introduce new evidence on new topics by using the techniques of cross-examination. This would be unfair to the party serving the hearsay notice, who may have had no notice of any of this.


The use of computer simulations as evidence in patent cases arises in a range of technologies, so the guidance that this must be approached using the law and rules relating to experiments is helpful. In particular, it will be useful to practitioners preparing cases where proof of infringement can only be done by computer simulation. 

The issue of court scientific advisers is controversial. The concern about using a separate court scientific adviser is that the parties are not privy to what that adviser says to the judge, and fear that he or she may unconsciously influence the judge’s view on a contentious issue. The court noted that assistance in other cases had sometimes been sought from patent examiners with expertise in the relevant field as they might be seen as being more impartial. Under the Unified Patent Court (UPC) system, patent litigators may have to become more familiar with this situation, as the UPC rules of procedure provide for the panel to include a technically qualified judge, who is not also legally qualified.

Case: Electromagnetic Geoservices ASA v Petroleum Geo-Services ASA and others [2016] EWHC 27 (Pat).

First published in the March 2016 issue of PLC Magazine and reproduced with the kind permission of the publishers. Subscription enquiries 020 7202 1200.