The Court of Appeal refused to grant an order of a blanket non-discovery (known in the UK as disclosure) of documents relating to obviousness of a patent in a patent infringement case. Accordingly parties are obliged to conduct a reasonable search of relevant documents, including inventor’s records. What is “reasonable” will depend on the facts of the case, such as the number of documents, complexity of proceedings and the amount at stake, etc.


Nichia, a Japanese company, sued the high-street store Argos for infringing its white LED patent by selling Christmas lights. Argos wanted to inspect the inventor’s technical records. This was resisted by Nichia. The UK High Court refused Argos’ application for disclosure of such records and Argos appealed.


The Court of Appeal found that a reasonable search had to be made of all relevant documents, including documents about the making of the invention.

The Court of Appeal found that the inventor’s thoughts, trials and tribulations are not important when assessing whether a patent is obvious. What matters is whether the skilled uninventive person would consider the step to be obvious. Nevertheless, contemporary events such as the inventor’s research can assist when testing the expert’s primary evidence because the question of obviousness is always considered in hindsight. Accordingly, documents such as the inventor’s records could in some circumstances be useful secondary evidence, although such evidence must be “kept firmly in its place”.

It is for this reason that the Court of Appeal rejected dispensing with disclosure as a matter of principle. To rule otherwise could result in relevant documents not being disclosed, and would enable parties to cherry-pick documents to suit their purpose. As the relevant court rule stipulates, a reasonable search must be carried out of all relevant documents. What is reasonable depends on the circumstances of the case, such as the number of documents involved, the complexity of the proceedings, the amount at stake, and the nature of the evidence being searched, including whether the evidence being searched is primary or secondary evidence.

Depending on the case, disclosure may be severely limited, or refused altogether by the court exercising its case management powers, but consideration must always be given to the needs of the particular case. It was only on this narrow basis that the appeal was allowed.

In this case, there were three judges sitting in the Court of Appeal; Lord Justice Jacob (“Jacob LJ”) who is the most experienced patent judge in the UK, and two other judges, Rix LJ and Pill LJ neither of whom are specialist in patent cases. Interestingly, in coming to the above decision, Rix LJ and Pill LJ overruled Jacob LJ. Jacob LJ made clear that in his experience there has been only a few cases where disclosure of an inventor’s records has been crucial, although it invariably racks up the legal costs of a case. Therefore, Jacob LJ held that disclosure on obviousness should not be given unless there are exceptional reasons for ordering it.


Most patent litigators would probably whole-heartedly agree with Jacob LJ. On first blush, the other two judges of the Court of Appeal may appear to have lacked an understanding of the reality of patent litigation. Rix LJ assumed that most patentees would as a matter of course review their own documents before mounting any patent infringement action, and so sorting out the disclosure of research documents would not be overly burdensome. To this extent, Rix LJ may be being a little too idealistic. However, all the Court of Appeal has done here is to reject the notion of non-disclosure of documents relating to obviousness as a matter of course. Each party instead has to consider carefully whether relevant documents (research records being one such type of document) could be reasonably found, and if this is the case that party must carry out such search.