Some cases of alleged prior use have been concerned with the extent of the EPO's obligation under Art. 114 EPC to examine of its own motion. In these cases, either the opposition had been withdrawn at the appeals stage and establishing prior public use had proved difficult, or the alleged prior use had not been substantiated.
In T 129/88 (OJ 1993, 598) the board took the view that the EPO's obligation to examine matters of its own motion did not extend as far as investigating an allegation of prior public use, where the party formerly making the allegation had withdrawn from the proceedings, and it was difficult to establish the facts without its co-operation (see also T 830/90, OJ 1994, 713; T 887/90, T 420/91).
In T 582/90 the board ruled that an objection of prior public use had to be examined if it appeared to be relevant, even if it had not been sufficiently substantiated.