c) Evidence of identity 

In T 1165/03 the board regarded an identity card or passport as the best evidence of identity but with the same proviso as applies to all evidence, i.e. that its value could be offset or even negated by other evidence. In this case, two partly illegible photocopies of different identity cards and inconsistent explanations had been filed. The board therefore held that the identity card evidence was inherently unreliable and inconclusive.

Questioning the identity of an opponent is not enough to render the opposition inadmissible; cogent evidence must be put forward. In T 4/05 no such case was made. The appellant had not filed the extract from the commercial register which, it submitted during oral proceedings before the board, showed a different company name. This could therefore not be cited as evidence that the opponent's identity was unclear. The appellant's objection that two other companies were trading at the same address as the opponent also failed.

In T 1426/13 the opposition had been filed on behalf of "Isarpatent GbR". The board noted that the lack of public registration of a GbR ("Gesellschaft bürgerlichen Rechts") could contribute to uncertainty or even confusion about the name and/or identity of a GbR at specific points in time. However, the EPO had to accept that such unregistered legal entities may be a party in proceedings before the EPO. Any relevant evidence had to be evaluated according to the principle of free and unfettered consideration of evidence (e.g. T 482/89, OJ 1992, 646). From the documents submitted the board was satisfied that a name change had occurred before the opposition was filed and that no other entity than Isarpatent GbR could have been the opponent. Nor was the admissibility of the opposition affected by any changes in the composition of the GbR after the opposition had been filed. A GbR may be held liable for its obligations, including costs which may be awarded to another party in EPO opposition proceedings. Therefore it was not necessary to determine the individual members (T 482/02 of 9 February 2005 date: 2005-02-09 distinguished).

In T 2439/17, the board considered the filed register extract to be evidence of the company's existence. The appellant had failed to cast any plausible doubt on this. The board further observed that neither being well known nor demonstrable business activity were among the EPC requirements for obtaining the status of opponent.