In J 16/82 (OJ 1983, 262) the Legal Board held that if an appeal was deemed not to have been filed, pursuant to Art. 108, second sentence, EPC 1973, because the appeal fee was not paid until after the expiry of the time limit for appeal, the purpose of the fee payment could no longer be achieved. The appeal fee must therefore be reimbursed, without the board of appeal having to give any specific order to that effect (see also T 324/90, OJ 1993, 33; T 239/92; T 1954/13). However, in T 79/01, T 1289/10, T 1535/10 and T 2210/10, where the appeal fee had also been paid late, reimbursement of the appeal fee was not ordered (see T 1553/13 date: 2014-02-20, OJ 2014, A84). See also in this chapter V.A.9.3.7.
In J 18/12 the Legal Board held that the final non-existence of the patent application in a substantive sense did not mean that the appeal proceedings had not come into existence (as opposed to the legal fiction of non-existence when an appeal was deemed not to have been filed). This situation regularly arose in proceedings before the EPO, e.g. where a decision of the Receiving Section not to accord a filing date was appealed.
In T 1325/15 the board addressed the question of whether an appeal had to be found inadmissible or deemed not to have been filed if the notice of appeal was filed, and the appeal fee paid, only after expiry of the time limit for filing the notice of appeal (see also T 2017/12, OJ 2014, A76, and T 1553/13 date: 2014-02-20, OJ 2014, A84). The board saw no compelling reason to deviate from the established approach of regarding an appeal filed out of time as deemed not to have been filed. Although the position that R. 101(1) EPC means that a late-filed notice of appeal brings into existence an inadmissible appeal might be not unreasonable, the board considered, in view of the general rule that no distinction was to be made between the late filing and the non-filing of a document, that no appeal exists where a notice of appeal was not (deemed to be) filed in due time. The board noted that its approach, although not always consistently applied in the jurisprudence of the boards of appeal, was also in line with the reasoning in earlier decisions that an appeal was deemed not to have been filed where the appeal fee had been paid in time but the notice of appeal had been filed only after expiry of the two-month period of Art. 108 EPC (see in particular J 19/90, T 445/98, T 778/00, OJ 2001, 554).