The principle of the protection of legitimate expectations applies to all procedural actions – whether formal or informal – taken by EPO employees vis-à-vis parties to proceedings (T 160/92, OJ 1995, 35; see also T 343/95; T 460/95 of 16.7.1996; T 428/98, OJ 2001, 494). It applies to both ex parte and inter partes proceedings (T 923/95). The requirements in connection with the principle of good faith to be observed by the EPO are the same visàvis all parties involved in proceedings before the EPO, be they applicants, patent proprietors or opponents (T 161/96, OJ 1999, 331, see also J 12/94). The principle of the protection of legitimate expectations also applies to acts performed by other authorities concerned in Euro-PCT proceedings during the international phase such as the US Patent Office acting as receiving Office or as International Preliminary Examining Authority (J 13/03). It applies also to the conduct of national authorities when dealing with European patent applications filed with them under Art. 75(1)(b) EPC (J 34/03).