4.2. Effects on the case law due to the differences between national legislation and the EPC

In J 9/07 the board stated that according to Art. 1 EPC 1973 the EPC established a system of law common to the contracting states for the grant of patents for inventions. This common system of law is applicable to all European patent applications irrespective of which contracting states have been designated in the European patent application. Although in general a high degree of harmonization between the EPC and national laws is desirable and has indeed been achieved, differences between national legislation and the EPC are not ruled out by Art. 2(2) EPC 1973 or Art. 66 EPC 1973 in this regard. The board stated that, save to the extent that the Convention expressly provides otherwise, the EPO is not allowed to take into consideration with respect to the designated state concerned a specific national legal provision which would be more favourable for the applicant than the provisions of the EPC. This is because this would have the consequence of giving European applications unequal treatment as regards the requirements for grant depending on which state or states have been designated, contrary to Art. 1 EPC 1973. It would also go against the principle of the unity of the application enshrined in Art. 118 EPC 1973 since, if a more favourable national provision were to be applied in relation to the designated state concerned, distinguishing between a case in which the designated state concerned is the only one designated and a case in which further states have been designated as well would appear arbitrary and unjustifiable.

As regard Art. 31(3)(a) to (b) Vienna Convention, legislative and administrative developments in a quarter of the contracting states did not amount to a subsequent agreement or practice (G 3/19).