I. The admissibility of the opposition must be checked ex
officio in every phase of the opposition and ensuing appeal
proceedings. It can and, where appropriate, must be raised by
the board in appeal proceedings even if this is the first time
this matter is addressed (T 289/91 OJ EPO 1994, 649; T 28/93,
reasons, 2, not published in the OJ EPO).
II. Admissibility of the opposition has to be judged on the
basis of the content of the notice of opposition as filed,
taking account of additional documents filed before the expiry
of the opposition period as far as they remedy any deficiency
fatal to the admissibility. Such a defect cannot be remedied
outside the period for opposition [Rule 56(1) EPC, in fine].
III. On the basis of statements contained in the notice of
opposition it must be possible to qualify whether the "instance"
or "aspect of the state of the art" was made available to the
public by means of a written or oral description, by use, or in
another way [Article 54(2) EPC] and of what it consists.
IV. In order to be substantiated pursuant to Rule 55(c) EPC the
notice of opposition must indicate "when", "what" and under what
circumstances, in particular "to whom", the alleged piece of
state of the art was made available.
V. The overall purpose of the admissibility requirement is to
allow the proprietor of the patent and the opposition division
to examine the alleged ground for revocation without recourse to
independent enquiries.
