Who is the Person Skilled in the Art? A Detailed Consideration at the IPEC

HHJ Melissa Clarke has given useful guidance on the criteria for determining the person skilled in the art, and the relevance of this to common general knowledge and hence inventive step.

Windsor successfully established that Urbis infringed its patents relating to LED street lighting technology. Urbis’s invalidity defence failed because it was unable to persuade the judge that the skilled person would have anti-climb safety considerations in mind.

The judge noted that a proper identification of the field of the skilled person must be neither too narrow nor too broad, because either of these extremes could lead to an unfair assessment of inventive step. A narrow approach might be based on identification of a problem which was not in fact known, leading to an incorrect finding of obviousness. In contrast, a broad approach might dilute the assessment of the skilled person’s common general knowledge, leading to an incorrect finding of inventive step. The identification should reflect reality at the priority date.

In this case, the judge held that the field of the skilled person was lighting support design, rather than a broader field including infrastructure health and safety. This meant that the skilled person was not focused on anti-climb considerations. As a result, the patents were novel and inventive.

A more detailed report on the decision (D.W. Windsor Limited v Urbis Schreder Ltd ([2025] EWHC 563 (IPEC)) will appear in the CIPA journal.