Common General Knowledge

Books and Databases in a Modern Library
Author Asturio Cantabrio  Licence CC BY-SA 4.0  Source Wikimedia Commons
 


 







 


Jane Lambert

27 Nov 2025

One of the conditions for the grant of a patent is that the invention involves an inventive step (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 (s.3 of the Act). The matter that forms part of the state of the art is the information that the skilled addressee would call to mind when considering whether an invention is obvious. Such information is referred to as "common general knowledge" and abbreviated to "CGK 

"State of the Art" 

 The reference to the state of the art is a bit misleading because it suggests that the skilled addressee would have access to all human knowledge in the relevant field.  In fact, it is a limitation in that the information must be available to the public.  The state of the art for the purpose of deciding whether an invention involves an inventive step is narrower than the state of the art for the purpose of determining whether an invention is new.  S.3 any matter which forms part of the state of the art by virtue only of s.2 (2) and specifically disregards matter falling within s.2 (3).

Summary 

The basic legal principles were summarized recently by Mr Justice Mellor in Pfizer Ltd v GlaxoSmithKline Biologicals SA and another 2024] EWHC 2523 (Pat) (7 Oct 2024) at para [80],  He said that the relevant law had been set out in KCI Licensing Inc v Smith & Nephew plc [2010] EWHC 1487 (Pat), [2010] FSR 31 at [105]-[112] and that "in order to form part of the CGK, information must be generally known in the art, and regarded as a good basis for future action. Material that would be found by routine research in the course of developing the cited prior art may be taken into account in assessing obviousness, but it is not CGK as such." 

KCI Licensing  

KCI Licensing is a judgment of Mr Justice Arnold and his discussion of the topic is thorough and comprehensive.  His starting point was Lord Justice Aldous's judgment in Beloit Technologies Inc v Valmet Paper Machinery Inc [1997] RPC 489 at 494:  

"It has never been easy to differentiate between common general knowledge and that which is known by some. It has become particularly difficult with the modern ability to circulate and retrieve information. Employees of some companies, with the use of libraries and patent departments, will become aware of information soon after it is published in a whole variety of documents; whereas others, without such advantages, may never do so until that information is accepted generally and put into practice. The notional skilled addressee is the ordinary man who may not have the advantages that some employees of large companies may have. The information in a patent specification is addressed to such a man and must contain sufficient details for him to understand and apply the invention. It will only lack an inventive step if it is obvious to such a man." 

He added: 

"It follows that evidence that a fact is known or even well-known to a witness does not establish that that fact forms part of the common general knowledge. Neither does it follow that it will form part of the common general knowledge if it is recorded in a document."

General Tire and Rubber

Lord Justice Aldous referred to the Court of Appeal's judgment in General Tire & Rubber Co. v. Firestone Tyre & Rubber Co. Ltd. [1972] R.P.C. 457 at 482:

"The two classes of documents which call for consideration in relation to common general knowledge in the instant case were individual patent specifications and `widely read publications'.

As to the former, it is clear that individual patent specifications and their contents do not normally form part of the relevant common general knowledge, though there may be specifications which are so well known amongst those versed in the art that upon evidence of that state of affairs they form part of such knowledge, and also there may occasionally be particular industries (such as that of colour photography) in which the evidence may show that all specifications form part of the relevant knowledge.

As regards scientific papers generally, it was said by Luxmoore, J. in British Acoustic Films (53 R.P.C. 221 at 250):
'In my judgment it is not sufficient to prove common general knowledge that a particular disclosure is made in an article, or series of articles, in a scientific journal, no matter how wide the circulation of that journal may be, in the absence of any evidence that the disclosure is accepted generally by those who are engaged in the art to which the disclosure relates. A piece of particular knowledge as disclosed in a scientific paper does not become common general knowledge merely because it is widely read, and still less because it is widely circulated. Such a piece of knowledge only becomes general knowledge when it is generally known and accepted without question by the bulk of those who are engaged in the particular art; in other words, when it becomes part of their common stock of knowledge relating to the art.'
And a little later, distinguishing between what has been written and what has been used, he said:
'It is certainly difficult to appreciate how the use of something which has in fact never been used in a particular art can ever be held to be common general knowledge in the art.'
Those passages have often been quoted, and there has not been cited to us any case in which they have been criticised. We accept them as correctly stating in general the law on this point, though reserving for further consideration whether the words 'accepted without question' may not be putting the position rather high: for the purposes of this case we are disposed, without wishing to put forward any full definition, to substitute the words 'generally regarded as a good basis for further action'."

 Raychem Corp's Patents

Mr Justice Arnold also referred to Mr Justice Laddie's judgment in Bourns Inc v Raychem Corp  [1997] EWHC 372 (Pat), [1997] EWHC 372, [1998] RPC 31] EWHC 372 (Pat) (12 June 1997) at 40 in para [106] of his judgment in KCI Licensing:

"The court is trying to determine in a common sense way how the average skilled but non-inventive technician would have reacted to the pleaded prior art if it had been put before him in his work place or laboratory. The common general knowledge is the technical background of the notional man in the art against which the prior art must be considered. This is not limited to material he has memorised and has at the front of his mind. It includes all that material in the field he is working in which he knows exists, which he would refer to as a matter of course if he cannot remember it and which he understands is generally regarded as sufficiently reliable to use as a foundation for further work or to help understand the pleaded prior art. This does not mean that everything on the shelf which is capable of being referred to without difficulty is common general knowledge nor does it mean that every word in a common text book is either. In the case of standard textbooks, it is likely that all or most of the main text will be common general knowledge. In many cases common general knowledge will include or be reflected in readily available trade literature which a man in the art would be expected to have at his elbow and regard as basic reliable information."

Information Not Part of the CGK but Likely to be Acquired

In para [108] of his judgment in KCI Licensing Mr Justice Arnold said that in several cases, notably Nutrinova Nutrition Specialties & Food Ingredients GmbH v Scanchem UK Ltd [2001] FSR 42 (Pumfrey J), Novartis AG v Ivax Pharmaceuticals UK Ltd [2006] EWHC 2506 (Pat) (unreported, Pumfrey J), and Ivax Pharmaceuticals UK Ltd v Akzo Nobel NV [2006] EWHC 1089 (Pat), [2007] RPC 3 (Lewison J), account had been taken of information that, while it was not part of the skilled addressee's common general knowledge, would have been acquired by him as a matter of routine before embarking on the problem to which the patented invention provides the solution.  Mr Justice Arnold quoted para [40] of Mr Justice Kitchin's judgment in Generics (UK) Ltd v Daiichi Pharmaceutical Co Ltd [2008] EWHC 2413 (Pat), [2009] RPC 4 which had referred to Mr Justice Pumfrey's judgments in Novartis v Ivax and Glaxo Group's Patent [2004] RPC 43:

"It seems to me that a subtle but potentially significant point of principle emerges from these passages. I can readily accept that, faced with a disclosure which forms part of the state of the art, it may be obvious for the skilled person to seek to acquire further information before he embarks on the problem to which the patent provides a solution. But that does not make all such information part of the common general knowledge. The distinction is a fine one but it may be important. If information is part of the common general knowledge then it forms part of the stock of knowledge which will inform and guide the skilled person's approach to the problem from the outset. It may, for example, affect the steps it will be obvious for him to take, including the nature and extent of any literature search."

 In Generics (UK) Ltd v Daiichi Pharmaceutical Co Ltd and another [2009] EWCA Civ 646, (2009) 32(9) IPD 32062, (2009) 109 BMLR 78, [2009] RPC 23, Lord Justice Jacob quoted the passage from Mr Justice Laddie's judgment that Mr Justice Arnold had quoted and said at para [25]:

"Of course material readily and widely to hand can be and may be part of the common general knowledge of the skilled person – stuff he is taken to know in his head and which he will bring to bear on reading or learning of a particular piece of prior art. But there will be other material readily to hand which he will not carry in his head but which he will know he can find if he needs to do so (my emphasis). The whole passage is about material which the skilled man would refer to 'as a matter of course.' It by no means follows that the material should be taken to be known to the skilled man if he has no particular reason for referring to it."

After quoting para [40] of Mr Justice Kitchin's judgment in Generics (UK) Ltd v Daiichi Pharmaceutical Co Ltd., Lord Justice Jacob said at para [27]:

"I agree with that although I personally do not find the point of principle 'subtle'. It would be wholly subversive of patents and quite unfair to inventors if one could simply say 'piece of information A is in the standard literature, so is B (albeit in a different place or context), so an invention consisting of putting A and B together cannot be inventive.' The skilled man reads each specific piece of prior art with his common general knowledge. If that makes the invention obvious, then it does. But he does not read a specific citation with another specific citation in mind, unless the first causes him to do so or both are part of the matter taken to be in his head."

Mr Justice Arnold's Summary

Mr Justice Arnold summarized the rule at [112] of his judgment in KCI Licensing:

"It follows that, even if information is neither disclosed by a specific item of prior art nor common general knowledge, it may nevertheless be taken into account as part of a case of obviousness if it is proved that the skilled person faced with the problem to which the patent is addressed would acquire that information as a matter of routine. For example, if the problem is how to formulate a particular pharmaceutical substance for administration to patients, then it may be shown that the skilled formulator would as a matter of routine start by ascertaining certain physical and chemical properties of that substance (e.g. its aqueous solubility) from the literature or by routine testing. If so, it is legitimate to take that information into account when assessing the obviousness of a particular formulation. But that is because it is obvious for the skilled person to obtain the information, not because it is common general knowledge."

Windsurfing/Pozzoli Test 

Identifying the skilled addressee's common general knowledge is the second step in the test for determining whether or not an invention is obvious in Windsurfing International Inc v Tabur Marine (Great Britain) Ltd. [1985] RPC 59 and Pozzoli Spa v BDMO SA and Another [2007] BusLR D117, [2007] 1 Bus LR D117, [2007] Bus LR D117, [2007] FSR 37, [2007] EWCA Civ 588.   However, Mr Justice Neuberger's observation at para [55] of DSM NV’s Patent [2001] RPC 35, that the first three questions or tasks are a means of disciplining the court’s approach to that fourth question of the test, namely whether the differences between the claimed invention and prior art constitute steps which would have been obvious to the person skilled in the art or whether they required any degree of invntiveness should always be noted.

Further Information

Cases applying those principles and relevant articles 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.

Case Law

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