a) General 

The state of the art is held to comprise everything made available to the public by means of a written or oral description, by use, or in any other way, before the date of filing of the European patent application (Art. 54(2) EPC). Use can take the form of producing, offering or marketing or otherwise exploiting a product, offering or marketing a process or its application or applying the process. Marketing may be effected, for example, by sale or exchange (see Guidelines G‑IV, 7.1 – March 2022 version).

Instances of public prior use or availability in any other way will typically be raised in opposition proceedings. Under established case law (see e.g. T 194/86; T 232/89; T 78/90; T 600/90; T 602/91; T 522/94, OJ 1998, 421; T 927/98; T 805/05), the following has to be clarified to determine whether an invention has been made available to the public by prior use: (i) when the prior use occurred, (ii) what was made available to the public through that use and (iii) the circumstances of the use, i.e. where, how and by whom the subject-matter was made public through that use.

See also: chapters IV.C.2.2.8 i) "Alleged public prior use"; V.A.5.13.6 "Public prior use"; and various sections in chapter III.G. "Law of evidence".

Although prior use is dealt with here in this chapter on novelty, specifically in its section on determining the prior art, it should be borne in mind that, whilst chiefly important in that context, what can be regarded as prior art is also relevant in examining inventive step (see e.g. T 1464/05 – public prior use as closest state of the art; T 23/11; T 2170/12).

Under Art. 114 EPC the EPO has only a limited obligation to undertake an examination of its own motion with regard to public prior use (T 129/88 (OJ 1993, 598) and T 34/94, on which see chapter V.A.3.3. "Facts under examination – applying Article 114 EPC in appeal proceedings").