d) Lack of clarity

The three options given in G 1/99 were set out with regard to the requirement of Art. 123(2) EPC. According to T 648/15 these options could be applied in a similar way when dealing with the requirement of Art. 84 EPC (see also T 1380/04). The board further noted, that the three options given in G 1/99 do not apply independently of one another and cannot be chosen ad libitum. Indeed, they are set out in such a way so as to indicate a particular sequence of options for overcoming the deficiency presented by a claim.

In T 974/10 the board emphasised that the Enlarged Board of Appeal had stated in G 1/99 that, "... if the patent cannot be maintained for reasons which were not raised at the first instance, the non-appealing proprietor deserves protection for reasons of equity". As, in the case at issue, the clarity objection was raised by the board for the first time in the appeal, the respondent had to be allowed to file amendments as foreseen in decision G 1/99, which decision gave due regard to the principle of equity.

In T 1845/16, the board concluded that making an exception to the prohibition of reformatio in peius in line with G 1/99 was warranted. The Enlarged Board of Appeal had held there that such an exception to the otherwise binding principle of the prohibition of reformatio in peius could be allowed for reasons of equity but was to be construed narrowly, stipulating that an impermissible feature could be deleted only if there was no other option for amendment that was less detrimental to the opponent. In the case in hand, the board could not identify any such option, nor had the appellant argued anything to that effect. Consequently, there was justification for making an exception to the prohibition of reformatio in peius and permitting the patent proprietor to overcome the lack of clarity in its main request by making the amendments to claim 1 requested in its auxiliary request 1.