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VPG Systems UK Limited v Air-Weigh Europe Limited, UK, High Court (Intellectual Property Enterprise Court), HHJ Hacon, 1 July 2015

On 1 July, HHJ Hacon ruled that the patent in suit was invalid for lack of inventive step. The relatively short judgment is of interest as it records the judge’s exposition of the English approach to answering the statutory question of what is obvious under the established Windsurfing/Pozzoli analysis generally adopted by the English courts.

Although many readers will be familiar with the four-step Windsurfing/Pozzoli approach to the obviousness question, it is worth setting out the steps:

(1a) Identify the notional “person skilled in the art”
(1b) Identify the relevant common general knowledge of that person;

(2) Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;

(3) Identify what, if any, differences exist between the matter cited as forming part of the “state of the art” and the inventive concept of the claim or the claim as construed;

(4) Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?

In relation to the second step, HHJ Hacon noted that the inventive concept is not the same as the inventive step.


In the Windsuring/Pozzoli approach the identification of the inventive concept comes before the assessment of the prior art and therefore does not vary. The inventive step, on the other hand, can vary according to the prior art under scrutiny, being the difference between the matter cited as forming part of the state of the art and the inventive concept of the claim (i.e. identified at step 3).

The judge was of the view that the inventive concept requires a determination of what the patentee asserts to be the essence of the invention as inferred from the words of the claim and the specification as a whole, and could be characterised as the product or process claimed shorn of the common general knowledge of the person skilled in the art. However, he also noted that identification of the inventive concept was optional, particularly when the parties could not agree what it is or where reaching a view on inventive concept would serve no useful purpose.

If the court elected to identify the inventive concept, it would apply the third and fourth steps of the Windsurfing/Pozzoli analysis as set out above. If it decided against, the approach would need to be modified slightly, and the prior art compared with the claimed invention as a whole. In this case, the judge decided to identify the inventive concept, but stated that he would cross-check the conclusion reached by taking the alternative approach. There was no suggestion from the judge that he would have reached a different conclusion on the alternative approach.

HHJ Hacon also reiterated that commercial concerns were not to be considered when assessing obviousness. Although all concerns and prejudices held by those in the field must be borne in mind, these only extended to technical ones. Therefore, a technically obvious but commercial unattractive advance was still obvious when assessing inventive step.

The judge also took the opportunity to note that there might have been an argument to support inventive step based on a long felt want, which is rarely argued in support of inventive step (or successful) nowadays. However, as the point had not been argued, the judge could not take such considerations into account when considering obviousness.

Read the decision here

Headnote: Gregory Bacon, Bristows