Should a board consider it necessary to deviate from an earlier opinion or decision of the Enlarged Board, the question must be referred to the Enlarged Board (Art. 21 RPBA).
In T 297/88 the board examined under which circumstances it was possible to re-refer a question which had already been decided by the Enlarged Board. It took the view that a board may only refer the same point of law another time to the Enlarged Board if the Enlarged Board's arguments were so weak that doubts as to the correctness of the decision were unavoidable. This was also the case where the arguments were based on a false premise so that there were doubts about the conclusion drawn. Finally, a decision of the Enlarged Board could also be questioned where the premise was correct, the arguments were conclusive and the conclusion therefore also correct, but where legal or technical developments occurring in the interim made it desirable in the public interest to have the question reviewed again by the Enlarged Board.
In G 9/93 (OJ 1994, 891), the Enlarged Board confirmed the referring board's view that the concept of opposition proceedings set out in G 1/84 differed fundamentally from that in G 9/91 and G 10/91, which it endorsed.