In case T 139/87 (OJ 1990, 68) the board of appeal made it clear that an appeal by an applicant for a European patent was to be considered well-founded within the meaning of Art. 109(1) EPC 1973 if the main request of the appeal included amendments which clearly met the objections on which the refusal of the application had been based as indicated by the examining division. In such a case, the department that issued the contested decision must rectify the decision. Irregularities other than those that gave rise to the contested decision do not preclude rectification of the decision (see also T 47/90, OJ 1991, 486; T 690/90; T 1042/92; T 1097/92; T 219/93; T 647/93; OJ 1995, 132; T 648/94; T 180/95; T 794/95; T 1120/11; T 410/14 and T 2303/16).

However, in T 615/95, where the examining division considered that interlocutory revision would only be possible on condition several objections were overcome and these objections were unrelated to the refusal and clearly had no link at all to the decision under appeal, the board held that such an approach had no legal basis.

According to T 1060/13 it is established case law of the boards of appeal that, in the event that the appeal is objectively to be considered as admissible and well-founded, the department of first instance is obliged to grant interlocutory revision (T 139/87, OJ 1990, 68; T 180/95; T 2528/12; T 1362/13); there is no room for discretion in the interests of procedural efficiency (G 3/03, OJ 2005, 344; J 32/95, OJ 1999, 713; T 919/95). In T 2445/11 the board was aware that its interpretation of Art. 109(1) EPC was not fully in line with the views expressed in T 1060/13, even though the outcome was the same. According to that decision, interlocutory revision must be allowed if the main request filed with the statement of grounds of appeal clearly overcomes the grounds for refusal, it being irrelevant whether amended claims give rise to new objections or suffer from deficiencies that are themselves the subject of observations included by way of obiter dicta. In the board's view, this approach may sometimes be too rigid, as it leaves no room for a pragmatic assessment of the situation with a view to procedural efficiency and may result in a needless repetition of the first-instance proceedings, forcing the applicant to pay a second appeal fee.

An appeal is to be considered "well-founded" if at least the main request submitted with the appeal includes amendments which clearly meet the objections on which the decision relies, such that the department of the first instance could reasonably be expected to recognise this and thus rectify its decision. That there are other objections which have not been removed but which were not the subject of the contested decision cannot preclude the application of Art. 109(1) EPC 1973 (T 139/87; T 47/90, OJ 1991, 486; T 219/93; T 919/95). Thus, even if the amendments raise new objections not yet discussed, interlocutory revision must be allowed since an applicant should have the right to two instances. Objections or remarks made in an obiter dictum of a decision under appeal cannot be taken into account (see e.g. T 1640/06 and T 726/10; the board disagreed with T 1034/11). Refusing interlocutory revision in the case of an admissible and well-founded appeal constitutes a breach of the duty to grant interlocutory revision in such a case and thus a breach of the principle of procedural efficiency (contrary to the finding in T 704/05) and cannot be regarded as a substantial procedural violation within the meaning of R. 103 EPC (see e.g. T 794/95).

In T 508/13 the board stated that the expression "considers the appeal to be ... well founded" in Art. 109(1) EPC leaves an examining division room for exercising judgment while bearing in mind that the purpose of interlocutory revision is to speed up the procedure (see T 2445/11). At the same time, once an examining division has decided not to rectify a refusal decision, the possible incorrectness or inappropriateness of not rectifying it is in itself insufficient reason for an immediate remittal of the case: the opportunity to cut short the appeal procedure by means of interlocutory revision has in any event passed. Rather, it has to be assessed whether an immediate remittal is appropriate in view of the overall state of the case.

In T 2445/11 the board accepted in principle that there are cases where amended application documents presented on appeal as the main request overcome the grounds for refusal yet do not warrant rectification of the decision because of other obvious deficiencies: deficiencies which are newly introduced and immediately apparent, or deficiencies which are well explained by remarks or objections included as obiter dicta in the decision to refuse and on which the applicant has had an opportunity to comment. But where, as here, an application has been refused by the examining division on grounds that were subsequently overcome, and more fundamental objections have not been well developed in the proceedings up to the refusal, there was little point in remitting the case to the boards of appeal.

In T 473/91 date: 1992-04-09 (OJ 1993, 630) the board made it clear that the admissibility question under Art. 109 EPC 1973 fell under the jurisdiction of the department of first instance only when this question could be decided immediately on the basis of the appeal submissions themselves. Consequently, the appellate instance had exclusive jurisdiction over a request for restitutio in integrum into a time limit relating to the appeal itself.

In T 919/95 the appellant was of the opinion that an interlocutory revision had to result in the appeal being allowed. A "cassatory" revision that merely set aside the contested decision and resumed the suspended proceedings was not compatible with the EPC. The interlocutory revision had to be a 'reformatory' revision, i.e. one that conferred on the appellant something that the contested decision deprived him of. The board stated that the requirements of Art. 109 EPC 1973 were met if the reason for the contested decision were removed as a result of an admissible appeal; once the contested decision had been set aside the requested decision could be taken, or the proceedings could be resumed, since further examination was required of new grounds or facts. The latter did not rule out a subsequent refusal. The purpose of interlocutory revision was to speed up the procedure. If an examining division rectified a decision under Art. 109 EPC 1973 merely in order to grant a patent according to an auxiliary request, even though the applicant insisted on his main request, the procedure was not thereby accelerated but slowed down and this would constitute a substantial procedural violation (see also T 142/96).