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Admissibility of Requests During Opposition Proceedings

By Michael Ford, Partner and Magnus Johnston, Partner

Recent EPO Board of Appeal decision T 1214/21 has confirmed that opposition divisions cannot arbitrarily restrict the number of claim requests to be considered during oral proceedings. Moreover, decisions on the admissibility and allowability of claim requests must be reasoned.


During opposition proceedings before the EPO, it is common for patent proprietors to submit multiple claim requests for consideration by the division. Theses typically include a main request in which the proprietor argues for their most preferred outcome – usually maintenance of the patent on the basis of the claims as granted or with relatively minimal amendments – and auxiliary requests defining narrower fallback positions. The opposition division should examine each of the requests in the order presented by the proprietor until one of the requests is found to be allowable or no requests remain. If a particular request is found to be allowable, the division will not consider any subsequent requests.

The EPO sets some limits on how and when proprietors may submit requests in which the patent is amended. For example, amendments must be occasioned by at least one of the grounds for opposition specified in Article 100 EPC (Rule 80 EPC) or be required to deal with an earlier national right (Rule 138 EPC). Amendments must also comply with the requirements for clarity (Article 84 EPC, subject to Enlarged Board of Appeal decision G 3/14) and the prohibitions against adding subject-matter (Article 123(2) EPC) and extending the scope of protection after grant (Article 123(3) EPC).

The EPO will also specify a deadline (under Rule 116(1) EPC) for making written submissions in preparing for the opposition oral proceedings and proprietors may submit requests at any time between receipt of the notice of opposition and this cut-off date. The division has discretion to disregard requests filed after this cut-off (including during the oral proceedings) as being “late-filed”. However, the division is required to admit late-filed requests necessitated by a change in the subject of the proceedings – for example, because the division has admitted new facts, evidence or grounds due to prima facie relevance, or because the division has changed its mind on a particular issue.

The division must assess all relevant factors when taking a decision on the admissibility of requests. This includes whether or not amendments are prima facie allowable, and whether the series of requests is “convergent” in the sense that it generally focusses towards a particular invention (i.e., the requests do not branch out in different directions covering substantially different subject-matter).

Importantly, when the opposition division decides not to admit a particular request, reasons for this decision must be given. The Guidelines for Examination (E-X, 1.3.3) at the EPO are clear that any statements of grounds issued by examining and opposition divisions must substantiate the reasons for their decisions. In particular, all significant arguments advanced by a party to the proceedings are to be examined carefully and comprehensively discussed in the final written decision.

T 1214/21

Recent Board of Appeal decision T 1214/21 concerns European patent EP2789585B1 entitled “Layered lithium nickel oxide, process for producing the same and lithium secondary cell employing it”, granted to SK Innovation Co., Ltd.

The patent claims protection for metal oxide particles for use in a cathode active material of a lithium secondary battery. The particles are defined in terms of a chemical formula LiaNixCoyMzO2, with the claims specifying possible elements for metal M and ranges of values for amounts a, x, y and z, and requiring a concentration gradient in which the concentration of metal M is decreased from the surface of the metal oxide particle towards its centre.

The patent was opposed by a straw man (i.e., a third party used to shield the identity of the real-world opponent) and was eventually revoked at the end of the oral proceedings.

As part of the opposition proceedings, the proprietor submitted various requests in which claim 1 was amended to redefine the composition of the metal oxide particle or to further characterise the concentration gradient. At the oral hearing, the opposition division rejected the main request as failing to comply with Rule 80 EPC and Article 123(2) EPC, as well as two auxiliary requests as not meeting the requirements of Articles 123(2) or 123(3) EPC. The division then stated that all further auxiliary requests on file “… presumably would have led to their non-allowability for the same reasons as the previously discussed requests”. The chair of the division also informed the proprietor that submission of only one further request would be permitted. The patent was eventually revoked.

However, on appeal, the Board found that the opposition division had erred procedurally in the way it treated the various auxiliary requests.

First, the Board noted that the written decision issued by the division after the oral proceedings did not contain any reasoning as to why the remaining auxiliary requests were not considered to be admissible and/or allowable. This was found to amount to a substantial procedural violation.

Second, the Board found that the division had committed a further substantial procedural violation by permitting only one further request during the oral proceedings without any consideration being given to the other requests already on file. In this regard, the Board cited earlier case T 756/18 concerning the refusal of an opposition division to admit more than one auxiliary request and rejecting all other auxiliary requests from the outset for no apparent reason.

In addition to these procedural matters, the Board found that auxiliary request 3, which was admitted into the appeal proceedings, complies with Articles 123(2) and 123(3) EPC.

The Board therefore set aside the decision of the opposition division, remitted the case for further examination of sufficiency, novelty and inventive step, and reimbursed the appeal fee.


This decision confirms that opposition divisions must carefully consider the admissibility (and if admitted, the allowability) of each request made by the proprietor and cannot arbitrarily restrict the number of the requests to be evaluated. Any final conclusions must also be substantiated.

Magnus Johnston, Partner in our Chemistry and Life Sciences and Materials teams, comments:

“T 1214/21 is a useful reminder that Opposition Divisions should not arbitrarily refuse to admit claim requests without good reason or simply because they are late-filed. On various occasions over the years I have encountered the Chair of an Opposition Division stating that “only one more request is permitted”, even in circumstances when the Opposition Division has reversed their preliminary opinion. Practitioners defending patents at first instance should be alert to and ready to challenge such practices during the hearing itself, armed with the Guidelines for Examination and Board of Appeal case law. Even practitioners attacking patents should be wary of such practices by the Opposition Division, since ultimately, like in T 1214/21, what might feel like a ‘win’ at first instance could lead to a 10-year or so ping-pong between the Opposition Division and Board of Appeal, with little or no legal certainty for the opposing third party during that period.”   

This is for general information only and does not constitute legal advice. Should you require advice on this or any other topic then please contact or your usual HLK advisor.

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