T 0750/94 (Proof of prior publication) of 01.04.1997

I. When an issue of fact is being examined and decided by the EPO on the balance of probabilities, the more serious the issue the more convincing must the evidence be to support it. If a decision upon such an issue may result in refusal or revocation of a European patent, for example in a case concerning alleged prior publication or prior use, the available evidence in relation to that issue must be very critically and strictly examined. A European patent should not be refused or revoked unless the grounds for refusal or revocation (that is, the legal and factual reasons) are fully and properly proved.

II. In accordance with the principle of "free evaluation of evidence" (see Decision T 482/89, OJ EPO 1992, 646) items of evidence relevant to a matter in issue must be given an appropriate weight in order to reliably establish what is likely to have occurred. An unsigned statement by an unknown and unnamed person should in principle be given minimal weight.