In an appeal procedure the provisions of Art. 114(1) EPC 1973 had to be interpreted in a more restrictive manner than in an opposition procedure and that, accordingly, fresh grounds for opposition raised by an opponent or referred to by a third party under Art. 115 EPC 1973 after expiry of the time limit laid down in Art. 99(1) EPC 1973 might in principle not be introduced at the appeal stage, unless the patentee agreed. (G 9/91, G 10/91, OJ 1993, 408, 420).
In T 667/92 of 27 November 1996, the board disregarded third-party observations because the patentee had not consented to their admission.
In T 1667/07 some documents which were copies of submissions made by third parties during the examination of the application were submitted as evidence in support of fresh grounds for opposition raised for the first time on appeal. The board pointed out that since it cannot consider the fresh grounds of opposition put forward by the appellant for the first time in appeal proceedings - as the patent proprietor opposed to their introduction into the proceedings - it cannot consider evidence submitted in their support either.