The right of parties to oral proceedings in examination, opposition and appeal proceedings is enshrined in Art. 116(1) EPC, according to which oral proceedings take place either at the instance of the EPO if it considers this to be expedient or at the request of any party to the proceedings. In other words, oral proceedings are not held automatically in each case. The right to an oral hearing is an extremely important procedural right which the EPO should take all reasonable steps to safeguard (T 19/87, OJ 1988, 268, T 663/90, T 808/94, T 911/04). If a request for oral proceedings has been made, such proceedings have to be appointed. This provision is mandatory and leaves no room for discretion (T 283/88, T 795/91, T 556/95, T 1048/00). Parties have an absolute right to oral proceedings (T 552/06, T 189/06, T 263/07, T 1426/07, T 653/08, T 1251/08, T 1829/10). Considerations such as the speedy conduct of the proceedings, equity or procedural economy cannot take precedence over the principle of the right to oral proceedings. The right to be heard in oral proceedings subsists so long as proceedings are pending before the EPO (T 598/88, T 556/95, T 114/09). The refusal of a request for oral proceedings normally constitutes a violation of the right to present comments. Thus, if the request for oral proceedings is ignored, even due to an oversight, the decision must be set aside as null and void (T 19/87, OJ 1988, 268; T 93/88, T 560/88, T 663/90 and T 766/90).
Where several parties are involved, e.g. in opposition proceedings, the EPC provides only for oral proceedings to which all the parties are invited, so as to respect the principles of judicial impartiality and the equal rights of parties T 693/95 .
The failure by the board to arrange for the holding of oral proceedings requested by a party may be a fundamental procedural defect on which a petition for review can be filed, see Art. 112a(2)(d) EPC, R. 104(a) EPC.
Besides Art. 116 EPC, there are also other provisions relevant for the preparation and conduct of oral proceedings: R. 115 EPC - summons to oral proceedings (see point 4.2. below), R. 116 EPC (R. 71a EPC 1973) - preparation of oral proceedings (see point 4.4. below), R. 124 EPC - minutes of oral proceedings (see point 4.8. below), as well as various notices concerning the practice for fixing the date of oral proceedings (see point 4.1.1 below). For the boards of appeal, see also Art. 15 RPBA.