The Skilled Addressee

Author km30192002  Licence CC BY 2.0  Source Wikimedia








  




Jane Lambert

25 Nov 2025

One of the conditions for the grant of a patent is that the invention involves an inventive step (see s.1 (1) (b) of the Patents Act 1977). An invention is taken to involve an inventive step if it is not obvious to a person skilled in the art, having regard to any matter which forms part of the state of the art (see s.3 of the Act). The "person skilled in the art" is a notional construct like the "average consumer" in trade mark law and the "informed user" in registered designs.  In Canada (though not in England), he is known as "the man in the Clapham omnibus of patent law" (see page 294 of the judgment of Mr Justice Hugessen in Beloit Canada Ltd. et al. v. Valmet Oy, 1986 CanLII 7621 (FCA) 64 NR 287, 38 ACWS (2d) 415, 8 CPR (3d) 289, [1986] CarswellNat 588, [1986] FCJ No 87 (QL), 8 RPC (3d) 289).

Mr Justice Laddie described the person skilled in the art as follows in Pfizer’s Patent [2001] F.S.R. 16 at para [62]:
"The question of obviousness has to be assessed through the eyes of the skilled but non-inventive man in the art. This is not a real person. He is a legal creation. He is supposed to offer an objective test of whether a particular development can be protected by a patent. He is deemed to have looked at and read publicly available documents and to know of public uses in the prior art. He understands all languages and dialects. He never misses the obvious nor stumbles on the inventive."
Mr Justice Carr made the following observations at para [25] of his judgment in Glaxosmithkline UK Ltd v Wyeth Holdings LLC [2016] EWHC 1045 (Ch):
"i) A patent specification is addressed to those likely to have a real and practical interest in the subject matter of the invention (which includes making it as well as putting it into practice).
ii) The skilled addressee has practical knowledge and experience of the field in which the invention is intended to be applied. He/she (hereafter "he") reads the specification with the common general knowledge of persons skilled in the relevant art, and reads it knowing that its purpose is to disclose and claim an invention.
iii) A patent may be addressed to a team of people with different skills. Each such addressee is unimaginative and has no inventive capacity.
iv) Although the skilled person/team is a hypothetical construct, its composition and mindset is founded in reality. As Jacob L.J. said in Schlumberger v. Electromagnetic Geoservices [2010] EWCA Civ 819; [2010] RPC 33 at §42:

'… The combined skills (and mindsets) of real research teams in the art is what matters when one is constructing the notional research team to whom the invention must be obvious if the patent is to be found invalid on this ground.'"

The person skilled in the art appears in several other contexts in patent law.  For example, s.14 (3) of the Act requires the specification of a patent application to disclose the invention in a manner which is clear enough and complete enough for the invention to be performed by a person skilled in the art.  It is not entirely certain that such person is the same in every circumstance.

Cases applying those principles are listed below, and these will be updated from time to time. Call me on +44 (0)20 7404 5252 during office hours or send me a message through my contact page for more information.
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