EPO - Evidence of Prior Use in Opposition Cases

In opposition proceedings a patent was revoked upon the basis of an unsworn witness declaration as to prior use. The declaration was contested and it was requested that the witness be summoned. However, the Opposition Division deemed that the prior use had been properly substantiated and did not summon the witness since the declaration was clear in what had been demonstrated to the public. The Opposition Division pointed to decision T674/91 which stated that one purpose of a declaration was to avoid having to call the person who had made it.

Upon appeal it was argued that the statements made in the declaration were unsubstantiated allegations and that if the disclosure was to be properly substantiated, the witness should be summoned to give evidence orally. The Board of Appeal expressed the position that the Opposition Division should have summoned the witness since he was available and his testimony turned out to be important for the decision. It was recommended that if the alleged facts are contested by the other party, the Opposition Division should not generally base its decision on such a statement, but should summon the person making the statement as a witness, if so offered by the party.

Decision T0959/00

The Opponent during opposition proceedings submitted evidence of prior use and also offered to produce a witness to substantiate the allegation of prior use on the basis of the evidence submitted.

The Opposition Division did not take up the offer of hearing the witness and determined that the evidence submitted was not sufficient to deprive the claims of novelty. The Opposition Division did not provide any reasoning as to why it considered the hearing of the witness unnecessary. In subsequent appeal proceedings, the Board of Appeal determined that the requirements of due process were not observed and that the Opposition Division’s failure to hear the witness, and the absence of any reference to a reason in the decision under appeal as to why, amounted to a serious and fundamental procedural violation (Article 113(1) EPC).