There are at least three reasons for reading this case. The first is that Mr Justice Pumfrey refused to consider evidence relating to representations made to patent offices on the ground that it was irrelevant to construction. His decision stymies, at least for the time being, the development of anything like prosecution or file wrapper estoppel in England. Secondly, it applies the principles set out by the House of Lords in Kirin-Amgen Inc and others v Hoechst Marion Roussel Ltd and others  UKHL 46 (21 October 2004) and subsequent cases. Finally, he considered whether there are any practical differences between the European Patent Office and the English courts in considering obviousness.
2. What this case was about
This was an application for a declaration of non-infringement in respect of one European patent under s.71 of the Patents Act 1977 and a claim for revocation of another. The inventions for which the patents were granted were for atorvastatin, a cholesterol synthesis inhibitor sold under the sign "Lipitor". So far as the application for the declaration of non-infringement was concerned the issue was one of construction. As the judge put it:
"Does the claim cover the single enantiomer which might be illustrated by formula (I) of the claim, or does it only cover racemic atorvastatin, that is the mixture of two enantiomers which Ranbaxy says is denoted by formula (I) on a proper interpretation of the formula in context."
The grounds upon which revocation was sought were obviousness and anticipation. The judge refused the declaration in respect of the first patent but he revoked the second patent for want of novelty and inventive step.
There are three main points to note. The first is that the judge distilled the following principle from Kirin Amgen and subsequent cases:
"I conclude that it is now clear that in deciding what the person skilled in the art would have understood the patentee to be using the language of the claim to mean, the court must approach the problem from the standpoint that the language chosen will be usually of critical importance. An over-meticulous analysis is one that is too willing to draw from a detailed analysis of the grammar, the punctuation and the particular words and phrases used inferences as to meaning that the words might support but which the skilled person would not draw, and it is the antithesis of giving to the words chosen in their context the meaning that the skilled person would give them. Carefulness is not to be equated with over-meticulousness."
Though the judge stated the principle with admirable clarity, one gets the impression that he did not find it particularly easy to apply. The second point is that the judge considered whether there was any practical difference between the English and EPO approaches to obviousness. As it happened, he did not but then he did find the patent bad for anticipation as well as obviousness. The last point is that early news reports had indicated that this was a win for the patentee. In fact it was only a win on the declaration of non-infringement. In the belief that it had been a total victory for the patentee one commentator was moved to write that it was a good day for patent professionals in England because it showed that the courts were not necessarily anti-patent. In fact, the outcome has turned out to be rather different.