Section 102(3): clerical error or obvious mistake
27 The onus to establish that the error is a clerical error or an obvious mistake lies with the patentee seeking the amendment: Expo-Net Danmark A/S v Buono-Net Australia Pty Ltd (2010) 88 IPR 1 at [14] (Bennett J) (Expo-Net).
28 The characteristic of a clerical error is not that it is in itself trivial or unimportant, but that it arises in the mechanical process of writing or transcribing: R v Commissioner of Patents; Ex parte Martin (1953) 89 CLR 381 at 406 (Fullagar J) (Ex parte Martin).
29 In Expo-Net, Bennett J considered the issue of "obvious mistake" and at [13] approved the statement of Graham J in General Tire and Rubber Co (Frost's) Patent [1972] RPC 259 at 279 that an obvious mistake is one that "the instructed public can, from an examination of the specification, appreciate the existence of the mistake and the proper answer by way of correction".
30 In Garford Pty Ltd v Dywidag-Systems International Pty Ltd [2014] FCA 1039, Yates J discussed the nature of a "clerical error" and "obvious mistake" and said the following at [14] to [19]:
14 In The Queen v Commissioner of Patents; Ex Parte Martin (1953) 89 CLR 381, Williams ACJ said (at 395):
… A clerical error, I would think, occurs where a person either of his own volition or under the instructions of another intends to write something and by inadvertence either omits to write it or writes something different. …
15 Fullagar J (with whom Kitto J and Taylor J agreed (at 408)) said (at 406), that the expression "clerical error" is of a "somewhat elastic character". After considering various dictionary meanings of the word "clerical", his Honour continued:
… Probably no one would deny that a clerical error may produce a significant, and even profound, effect as for example, in a case in which a writer or typist inadvertently omits the small word "not". But the characteristic of a clerical error is not that it is in itself trivial or unimportant, but that it arises in the mechanical process of writing or transcribing. …
16 In General Tire & Rubber Company (Frost's) Patent [1972] RPC 271, Graham J (at 279) considered an "obvious mistake" to be one which:
… involves that the instructed public can, from an examination of the specification, appreciate the existence of the mistake and the proper answer by way of correction.
17 In reaching that conclusion, his Lordship distinguished between such a mistake and a mistake that had been "obviously made". His Lordship (at 278) explained the distinction as follows:
It is the mistake which must be obvious and not the fact that it has been made. This implies, to my mind, that both the fact of mistake and the correction necessary must be clear to the reader's mind, and it is not enough if he merely appreciates the presence of a mistake. If, in a mathematical context, it is said "2 and 2 make 5", the reader would immediately say: "5 is an obvious mistake for 4". If, however, there is more than one possible correct answer to the question, particularly where the answers may depend on intention or judgment, the reader would say: "Obviously a mistake has been made but I cannot tell you what is the right answer". The wording of the section itself therefore, to my mind, shows an intention in favour of the first construction rather than the second.
18 In the course of considering that question, his Lordship observed (at 277) that, for the purpose of correcting an obvious mistake:
… it does not matter that the claim may be enlarged by the amendment.
19 Both these cases accept that the correction of clerical errors and obvious mistakes may involve the making of very significant amendments to the specification and, in particular, the claims. Yet, such amendments are allowable if they are truly "clerical errors" or "obvious mistakes".
31 A mistake can be an obvious mistake even where trained minds have failed to notice that mistake for "quite a long time", as Russell LJ further explained in Farmhand Inc v Spadework Ltd [1975] RPC 617 (Farmhand) at 619-20:
One is familiar, in all sorts of realms, with the fact that a person who may be in fact responsible for the production of a document may know perfectly well what he means to say and may well think he has said it, and is therefore the last person who is likely to notice that he has failed to say it by mistake. If one really set a standard… that a mistake cannot be an obvious mistake because a trained mind has failed to notice it, then of course… you could never have an obvious mistake in a patent, because some trained mind at some stage has produced that document and has not noticed the mistake… In some sense it may be true to say that the more glaring (and therefore the more unexpected) the mistake is, the less likely is anybody with a skilled mind to notice it. They simply would not believe that it could be there; and this is just that kind of mistake.