G 0003/97 (Opposition on behalf of a third party) 21-01-1999

Reasons for the Decision

1. Both referrals essentially pose the question whether an opposition is inadmissible if the opponent is acting on behalf of another person, ie as a straw man (question 1 in T 301/95 and question 3 in T 649/92). In accordance with established case law (see, for example, T 798/93, OJ EPO 1997, 363 - Identification of real opponent/ROAD TRAIN, with further references and decisions quoted in Case Law of the Boards of Appeal of the EPO, 2nd ed., 1996, section VI.D.3.2.2), the respondents invoked the principle that a person acting on behalf of a third party was not the true opponent.

2. The Board is unable to accept this premise.

2.1 The status of opponent is a procedural status and the basis on which it is obtained is a matter of procedural law. The EPC addresses this in Article 99(1) in conjunction with Article 100, Rules 55 and 56(1) EPC. On this basis, the opponent is the person who fulfils the requirements of the EPC for filing an opposition; in particular, the person must be identifiable (see Rule 55(a) EPC). The EPC does not specify any further formal requirements to be met by the opponent. A person who fulfils the said requirements becomes a party to the opposition proceedings (Article 99(4) EPC). In these proceedings, only his acts are relevant. A third party (the "principal") who has incited the opponent to file the opposition cannot perform any procedural acts. The question whether the opponent's acts accord with the intentions or instructions of the principal is relevant only to the internal relationship between the latter and the opponent, and has no bearing on the opposition proceedings.

By contrast, it has been argued that a person acting on behalf of a third party is not acting in his own name (T 10/82, OJ EPO 1983, 407 - Opposition; admissibility/BAYER, Reasons point 3). However, such a view is expressly contradicted by the opponent's procedural statements. He has neither stated that he wishes to file an anonymous opposition, nor is this his intention; instead, he expressly wishes to file the opposition in his own name. In T 635/88 it was said that the action at law instituted by a person acting with the personal action at law of someone else must be prohibited (OJ EPO 1993, 608 - Opponent identifiability/DE ERVEN G. DE BOER B.V., Reasons point 8.3). However, the opponent does not wish to act on the basis of the principal's personal entitlement. Instead, he is exercising his own right as a member of the public to file an opposition.

2.2 The opponent does not have a right of disposition over his status as a party. If he has met the requirements for an admissible opposition, he is an opponent and remains such until the end of the proceedings or of his involvement in them. He cannot offload his status onto a third party (see, on this issue, referral T 649/92, Reasons point 2.2). Thus there cannot be another "true" opponent apart from the formally authorised opponent. From this it follows that it is not only on the basis of a presumption that the person meeting the requirements for admissibility in his own name is treated as the opponent.

3. Accordingly, an opposition on behalf of a third party complies with the provisions on filing oppositions and there would have to be special reasons for investigating, with a view to assessing the admissibility of the opposition, the question whether or not the person who has filed the opposition in accordance with those provisions is acting as a straw man.

3.1 Such a special reason is briefly mentioned in G 1/84 (OJ EPO 1985, 299 - Opposition by proprietor/MOBIL OIL). Taking the, from their point of view, hypothetical case of a patent proprietor who was barred from filing the opposition himself (see, more recently, G 9/93, supra), the Enlarged Board assumed that the patent proprietor would, if necessary, be induced to employ a straw man as the putative opponent. Since the connection between patent proprietor and straw man was not apparent, there was a risk that the opposition procedure could be abused for ulterior purposes (G 1/84, supra, at page 301, point 2). This was clearly seen as an example showing that a straw man can be used to secure a successful result which is out of keeping with the legal system. Such an abuse of process does not have to be tolerated.

3.2 However, acting on behalf of a third party cannot be seen as a circumvention of the law unless further circumstances are involved. The purpose of opposition proceedings alone does not offer sufficient grounds for regarding an opposition on behalf of another person as an abuse of the procedural provisions.

3.2.1 The respondents have argued that the patent proprietor, the EPO and the public had an interest in knowing the identity of the person at whose instigation the opposition had been filed. Though the patent proprietor may have an economic interest in finding out who is trying to attack his patent, such an interest is not legally protected by the legislative arrangements for the opposition procedure.

Some of the EPC contracting states require, as a precondition for instituting revocation proceedings, that the plaintiff must have an interest in the invalidation of the patent. Taking a different approach, the EPC legislator explicitly designed the opposition procedure as a legal remedy in the public interest which, according to Article 99(1) EPC, is open to "any person". It would be incompatible with this to require that the opponent show an interest, of whatever kind, in invalidating the patent (G 1/84, supra, at page 303, point 3; Mathély, Le droit européen des brevets d'invention, Paris 1978, page 297; Paterson, The European Patent System, London 1992, paragraph 4-38, still referring to G 1/84 (supra); van Empel, The Granting of European Patents, Leyden 1975, paragraph 469; Singer, Article 99 EPC, paragraph 3).

3.2.2 If, therefore, it cannot be required that the opponent have an interest in the revocation of the patent, then logically this can only mean that the opponent's motives are of no consequence for the EPO, at least as long as no conduct involving an abuse of process arises from additional circumstances. As a matter of principle, therefore, the patent proprietor cannot expect the EPO to compel the opponent to disclose his motives in order to exclude the possibility that he may be acting in the interest of a third party.

This also applies where the opponent is in fact acting in the interest of a third party. By filing the opposition, he himself has assumed the procedural status of an opponent. Therefore, in relation to the patent proprietor and the EPO, he is the only person who matters. If, for the purpose of opposition, the opponent does not need to show an interest in the invalidation of the patent, then no harm is done if a third party has an interest in the invalidation of the patent. The question of the internal legal relationship between the opponent and any third parties has, as a matter of principle, no legal significance for external purposes, ie vis-à-vis the EPO and the patent proprietor. At all events, as long as the legal system has no objection to the filing of an opposition by the principal himself, no objection can be made to his inciting a straw man to file an opposition (this principle has even been applied to revocation proceedings; see BGH GRUR 1963, 253 - Bürovorsteher). Furthermore, it is correctly pointed out in the referral T 649/92 (Reasons point 2.6) that the opponent and his principal may have differing degrees of interest in opposing a patent. This interest may also change or be eliminated in the course of the proceedings, so that cases of doubt may arise which are difficult to assess. Finally, the question would remain of when an interest of the opponent would be regarded as relevant for the opposition. The appellants have pointed out that an interest of the opponent in the outcome of the opposition proceedings could arise from the division of responsibilities between different, legally independent companies within the framework of a large group, from some form of quid pro quo offered by the principal, or even from the wish to avoid an order for the reimbursement of costs under Article 104 EPC.

3.2.3 All this shows that the opponent's motives are of no consequence for the purposes of the opposition procedure.

This procedure is designed to give the public the opportunity to challenge the validity of the patent in question (G 9/93, supra, Reasons point 3). This takes account, inter alia, of the fact that a patent office cannot be aware of all the actual circumstances which argue against patentability. For the purpose of the opposition procedure - to prevent the maintenance of clearly invalid patents, by making it possible to institute proceedings before the EPO itself - it does not matter who provides the EPO with the relevant information (see also T 798/93, supra, Reasons point 4, final paragraph). Opposition should be a simple, speedily conducted procedure in which, on the one hand, relevant objections to patentability are given appropriate consideration, and on the other hand, a decision on the validity of the patent is reached as quickly as possible, in the interests of both parties. In this respect, investigating a straw man challenge would mean that more matters in dispute would have to be considered, which could delay the proceedings. Setting limits, not provided for by the EPC, on the admissibility of oppositions would conflict with the public interest in each opposition being examined on its merits and in having the proceedings brought to a swift conclusion (see G 1/84, supra, at page 303).

In consequence of the restricted purpose of the opposition procedure, the EPO has only inadequate procedural means for ascertaining whether a straw man is involved. For example, it cannot compel a party to attend the proceedings or to make a statement under oath (see Article 117(4) and (5) and Rule 99 EPC). This situation may have contributed to the development of the previous case law, which has established a presumption that the opponent is not acting as a straw man. This presumption could only be refuted in practice by the patent proprietor unmasking himself as the principal (T 635/88, supra, Facts, point III), or through his being unmasked by the opponent (T 10/82, supra, Facts, point VIII). In all other cases, the boards have refused to investigate concrete and plausible grounds cited by the patent proprietor for suspecting that the opponent was acting on behalf on a third party. Although the two referrals appear to anticipate different answers to the legal question under consideration, both boards agree that the situation on the basis of previous case law is unsatisfactory. On the one hand, the straw man objection has been allowed, which in many cases has created additional matters of dispute to be considered. On the other hand, the patent proprietor has been denied the possibility of successfully basing this objection on the actual circumstances, which are normally known to him.

Another reason for the high standards of proof in previous case law concerning action by a straw man must be seen in the fact that the opponent is rarely able to refute circumstantial evidence submitted by the patent proprietor, except by revealing his motives for the opposition. However, the purpose of the provision in Article 99(1) EPC is precisely that the opponent should not be required to have any kind of interest and therefore should not have to prove such an interest (see point 3.2.1 above). The opponent may not therefore be allowed to suffer a disadvantage purely because he has no such interest. It is also necessary to protect the opponent's interest in not being obliged to reveal to the patent proprietor why a patent disturbs him. His opposition is already fully justified by the fact that he, like anyone else, has to respect the patent if it remains valid, which means at all events that an abstract restriction is imposed on his freedom of economic action. The assumption of an obligation to show an adverse effect on specific commercial planning would be entirely at odds with the purpose of the legal provision.

3.2.4 The admission of an opponent acting on behalf of a third party is not incompatible with the inter partes character of the opposition procedure (see also, however, point 4.1 below). The formally authorised opponent is treated as a party. For him, the existence of a principal is neither an advantage nor a disadvantage during the proceedings. The fear that undisclosed contacts between straw man and principal could lead to doubts and uncertainties (see for example T 798/93, supra, with further references, Reasons point 3.3.4) would only apply to opposition proceedings on the assumption that there can be a "true opponent" in addition to the formally authorised opponent. There is no basis for this in the relevant procedural law (see point 2.2 above).

3.2.5 In the referral decision T 301/95 (Reasons point 3.5), attention is drawn to the risk that any lack of clarity in the position of the parties and witnesses in relation to each other, or that of any other persons giving evidence, may impede the process of finding the truth. However, since only the formally authorised person is to be seen as the opponent, the principal will under no circumstances be treated as a party. In any event, therefore, doubts about the position of the parties cannot arise.

However, in the case of persons giving evidence who have some form of relationship with the principal, their position with regard to the pending proceedings will not be apparent. But this cannot be seen as significantly impeding the process of finding the truth. The EPC does not in any way guarantee that the person with the strongest interest in the revocation of the patent will act as the opponent. Even supposing that the opposition were inadmissible if the opponent had no interest of his own, the patent proprietor's strongest competitor could hide behind an insignificant competitor as the opponent and provide him with material. The key criterion for the credibility of a person giving evidence in the present connection is that person's interest in the outcome of the opposition proceedings, which is not necessarily documented in a relationship to the opponent. For this reason the EPO is obliged to assess the credibility of any person giving evidence and to establish in what way he (or, for example, his employer) is affected by the outcome of the opposition proceedings (see also referral T 649/92, Reasons point 2.9).

3.2.6 It is also unnecessary to know that the opponent has a principal in order to ensure that costs awarded against the opponent under Article 104(1) EPC are reimbursed to the patent proprietor. As has already been explained, only the opponent is a party to the proceedings. He alone must bear the obligations arising from these proceedings; thus he becomes the debtor in respect of any claim for the reimbursement of costs. The EPC does not offer the patent proprietor any kind of guarantee that an opponent will be able in fact to reimburse costs awarded against him.

3.2.7 In the referral decision T 649/92 (Reasons point 2.1), a parallel is drawn between the procedural status of the opponent and that of the applicant. In the case of the applicant, a discrepancy may arise between the substantive legal position based on the invention (Right to a patent, Article 60(1) and (2) EPC) and the procedural position based on the filing of the application. Addressing this potential conflict, the legislator has decided that, in proceedings before the EPO, the applicant shall be considered to be entitled to exercise the right to the patent (Article 60(3) EPC), and that jurisdiction for any dispute over the claim to the grant of the patent shall lie with the national courts (Article 61 EPC in conjunction with the Protocol on Recognition). The appellants correctly point out that an applicant remains entered in the Register even if the EPO finds out that the right to a patent has been assigned to a third party. The EPO only records a transfer if it receives a request complying with the relevant formal requirements (Rule 20 EPC). The EPO should not be burdened with the question whether the applicant is also the person entitled to exercise the right to the patent (van Empel, supra, paragraph 162). It would be somewhat paradoxical to relieve the EPO - in the interests of procedural economy and the proper consideration of the substantive issues - of any obligation to look for the "truly entitled" person in the grant procedure, but then to include the consideration of comparable issues in the opposition proceedings, even though there cannot be another "true opponent" in addition to the formally authorised opponent, but only a principal of the opponent.

3.3 There are also no grounds outside the opposition procedure for generally ruling out an opposition on behalf of a third party.

3.3.1 In referral T 301/95, in particular, emphasis is laid on the point that a decision in the European opposition proceedings could give rise to an objection of res judicata in subsequent national revocation proceedings. Here, the involvement of a straw man in the opposition proceedings is evidently seen as prejudicial to the patent proprietor, who can plead res judicata against the opposing party in revocation proceedings. This plea assumes, inter alia, that the parties are identical. If the involvement of the straw man's principal is not apparent, the patent proprietor will not be in possession of the relevant facts for the purpose of raising the objection.

This line of argument is refuted, firstly, by the fact that the question of res judicata does not arise in opposition proceedings; here, it is purely hypothetical, since as a general rule revocation proceedings are only instituted later. It is only in revocation proceedings that the basis for the res judicata objection can be considered. It is not clear why the court in revocation proceedings should not be in a position to establish whether the person filing for revocation has incited a straw man to lodge an opposition before the EPO. Moreover, a straw man may also be involved in revocation proceedings, so that, even if it is established beyond all doubt in opposition proceedings that the opponent is not a straw man, there is no guarantee of being able to establish without difficulty in revocation proceedings that the requirements in respect of the parties involved in order for res judicata to apply have been met. Establishing this may also involve looking at all the circumstances of both sets of proceedings - opposition as well as revocation. In any event, therefore, only the court in the revocation proceedings will have an overview of all the relevant circumstances. Furthermore, a decision of the EPO on the possible involvement of a straw man would not have a binding effect in subsequent revocation proceedings. From the above it follows, firstly, that the patent proprietor's scope for raising the res judicata objection is not restricted if opposition by a straw man is considered to be admissible. It also follows that the consideration of the straw man issue in opposition proceedings would lead to the risk of a conflicting decision on the same question in subsequent revocation proceedings. As has already been explained, the EPO lacks the procedural scope for investigating a straw man challenge (see point 3.2.3 above). By contrast, the national courts can use all the customary and proper instruments of civil procedure to clarify the facts.

3.3.2 In the view of the respondents, the possibility of opposition on behalf of a third party could induce a licensee to infringe an existing no-challenge agreement. However, a person bound by a no-challenge obligation would have good reason not to infringe it by means involving the use of a straw man. If the patent proprietor has concrete grounds for suspecting such infringement, he can bring a civil action against the other party to the agreement, who is therefore put at considerable financial risk. By contrast, the EPO - in this case, as in others - has almost no procedural means of compulsorily eliciting the truth of the actual circumstances from an opponent who deliberately sets out to conceal the existence and identity of a principal.

However, previous decisions offer no reason to fear that no-challenge obligations might be circumvented to any significant extent by means involving the use of a straw man. At all events, although the straw man objection has been raised many times, the boards of appeal have yet to hear a single case involving an allegation that an opponent's principal was bound by a no-challenge agreement.

It must also be remembered that the effect and scope of no-challenge agreements depend on national and European Community law, and that the admissibility of such agreements is a controversial issue, in particular under European Community law. Consequently, in respect of the law to be applied, as in other aspects, these matters tend to fall within the remit of the national courts. In a decision dated 13 May 1992 (OJ EPO 1992, 747 - No-challenge obligation), an opposition division therefore rightly concluded that a no-challenge agreement did not as a rule render an opposition inadmissible. The patent proprietor's attempt to enforce adherence by the licensee, or to pursue claims arising for breach of contract, had to be made before the national courts.

3.3.3 In G 1/84 the fear is incidentally expressed that the employment of a straw man could serve to abuse the opposition procedure for ulterior purposes, eg to delay proceedings before another court (supra, at page 301, in connection with the straw man employed by a patent proprietor who is not allowed to file the opposition himself). It is by no means clear that such a risk exists. If the straw man can delay the proceedings, then surely his principal could do the same. The parties can influence the progress and length of the opposition proceedings mainly through two factors: the contents of their submissions and their procedural requests. Here, the straw man's possibilities would not appear to differ significantly from those which would be open to the principal if the latter himself were a party. Moreover, it is the duty of the EPO departments dealing with the opposition proceedings to oppose any obvious delaying tactics and to comply with the legitimate interest of a party in accelerating the proceedings (see, for example, T 290/90, OJ EPO 1992, 368 - Fee reduction/SAVIO PLASTICA; conclusion as in referral T 649/92, Reasons point 2.4).

4. Since there is no general objection to the opponent's acting on behalf of a third party, it remains to be established in what circumstances the action of a straw man is to be regarded as a circumvention of the law by abuse of process, with the consequence that the straw man's opposition is inadmissible.

4.1 Attention has already been drawn to the decision in G 9/93 (above, point 3.1). Here, it was decided that the patent proprietor is not entitled to oppose his own patent, since opposition proceedings are contentious and the opponent must therefore be a person other than the patent proprietor. This in itself requires no further comment. However, if the patent proprietor employs a straw man, then the latter, too, is representing the patent proprietor's interests. The identification of the straw man as opponent according to Rule 55(a) EPC does nothing to alter the fact that the person who is formally a party to the proceedings is on the patent proprietor's side. From this it follows that in this situation, too, the proceedings are not contentious. The employment of the straw man merely serves to conceal this circumstance and to circumvent the legal consequences arising from it. The action of the opponent on behalf of the patent proprietor therefore renders the opposition inadmissible.

4.2 Referral T 301/95 (supra, point 3.4) identifies a risk that the provisions on representation could be circumvented by the use of a straw man.

4.2.1 This fear is justified if persons are acting in a professional capacity before the EPO without possessing the necessary qualifications for doing so. Under Article 134(1) and (7) EPC, professional representation in proceedings before the EPO may only be undertaken by persons whose names appear on the list of professional representatives, or by legal practitioners who have their place of business in one of the contracting states and are qualified to act as professional representatives in patent matters. Therefore, for example, a patent attorney qualified only under the national law of a contracting state is not entitled to act as a professional representative before the EPO. The purpose of this arrangement is to create a corpus of professional representatives who possess the necessary qualifications for their work. This is designed to protect the parties that have to rely on the services of a professional representative, and to ensure the efficient conduct of proceedings before the EPO. This legislative purpose would be contradicted by applying the procedural provisions in such a way as to allow a person who was not entitled to act as a professional representative to carry out the functions reserved for professional representatives. However, this would be the case if the person not entitled to act as a professional representative were acting on a client's behalf and carrying out all the activities typically carried out by professional representatives, while himself assuming the role of a party in order to circumvent the prohibition on his acting as a professional representative. Taking on the additional party role of an opponent does nothing to alter the fact that the activities as a whole fall within the sphere of professional representation. The idea of a corpus of professional opponents is foreign to the EPC. Allowing such professional opposition would undermine, for an important part of the proceedings before the EPO, the monopoly status of the professional representatives. If a person not entitled to act as a professional representative before the EPO files an opposition in his own name on behalf of a client, in the context of activities which, taken as a whole, are typically associated with professional representatives, that opposition is therefore inadmissible.

4.2.2 However, such misgivings do not arise if a professional representative files an opposition in his own name on behalf of a client. Here, too, as in the previous case, the existence of a client is not disclosed. However, no attempt is being made to achieve a result which is fundamentally at odds with the EPC. The problem of action by a person not entitled to act does not arise. In other respects, too, the Convention contains no principles that would be contravened by the case of a professional representative acting on behalf of a third party in his own name. The respondents have argued that such action would become the rule if it were permitted, and that such a development would be undesirable. However, this does not necessarily mean that such action would conflict with the Convention. There may be reason to question, as in T 10/82 (supra), the desirability of combining the roles of party and representative. However, in the absence of contrary principles, which have to be based on the Convention, this is more an issue of professional conduct. In this connection, it has not been alleged that the conduct criticised by the respondents infringes the Regulations on Discipline adopted on the basis of Article 134(8)(c) EPC.

4.2.3 There are equally few misgivings in the case of an opponent, with either a residence or principal place of business in one of the contracting states, acting on behalf of a principal who does not meet these requirements. In this case, admittedly, the representation requirement which the principal would have to fulfil under Article 133(2) EPC cannot be applied. But this is merely the consequence of the fact that the opponent has admissibly become a party. In so far as procedural issues depend on the opponent's identity, the sole determining aspect consists in the personal circumstances of the person formally identified in accordance with Rule 55(a) EPC. Here, there is no reason to apply a standard different from that which has to be met by the applicant. In the case of the latter, no investigation is carried out to ascertain whether he is merely acting as an applicant in order to circumvent the representation requirement for a possible principal.

5. Since opposition in a person's own name and on behalf of a third party is inadmissible in case of a circumvention of the law by abuse of process (see point 4 above), the question arises of how and under what circumstances the possibility must be investigated that such an opposition has been filed (question 2 in T 310/95, question 4 in T 649/92).

Regarding the issues of evidence raised in the referrals, it must be emphasised that proceedings before the EPO follow the principle of the free evaluation of evidence. This also applies to the problems under consideration here. The principle of free evaluation would be contradicted by laying down firm rules of evidence defining the extent to which certain types of evidence were, or were not, convincing. Instead, the question whether a fact can be regarded as proven has to be assessed on the basis of all the relevant evidence.

In apportioning the burden of proof, general principles also apply. The burden of proof for a straw man objection is to be borne by the person raising the issue, ie the patent proprietor or, in the case of an objection by the Office of its own motion, the relevant EPO department.

Regarding the standard to be applied in assessing evidence, it must be remembered that any person is entitled to file an opposition. Withholding this legal entitlement from anyone requires a particular justification, which cannot be based on a mere balance of probabilities. Instead, before considering an opposition to be inadmissible, the deciding body has to be satisfied, on the basis of clear and convincing evidence, that the law has indeed been circumvented in an abusive manner by the employment of a straw man.

5.1 In other respects, there are certain fundamental differences between the cases cited in points 4.1 and 4.2.1.

5.1.1 If a patent proprietor employs a straw man to file an opposition, then the admissibility of the opposition will not normally be queried by any of the parties, since the patent proprietor wishes to pursue the proceedings through his straw man. In practice, therefore, the objection that the opponent is not entitled to file an opposition can only be investigated by the EPO of its own motion.

However, the EPO will as a rule have no indication that a straw man has filed an opposition on the patent proprietor's behalf, unless the parties themselves make it clear that this is the case. This means that the employment of a straw man will normally have no consequences and that the inadmissibility of the opposition will not be detected. However, this is no basis for arguing in favour of generally allowing opposition by a straw man acting for the patent proprietor. It makes an important difference whether an abuse of process has no consequences because it remains undiscovered, or whether such abuse is openly accepted. If the patent proprietor's straw man is prohibited in principle from filing an opposition, then this at least forces the parties to conduct the proceedings on an inter partes basis. Otherwise, they must accept the possibility that the straw man's involvement may come to light. Relevant indications that the opponent is a straw man acting for the patent proprietor can emerge, in particular, from the relationship between the two; for example, where the opponent is bound by the proprietor's instructions as a subsidiary company within the framework of a large group or as an employee of the patent proprietor.

5.1.2 If the question arises whether someone is acting as an opponent before the EPO on behalf of a client without being qualified as a professional representative, then here too, it has to be remembered in the first place that any person is allowed to file an opposition. That an opponent is acting as a straw man cannot therefore be inferred purely from the fact of belonging to a particular group of professional persons. However, if a person offers his services to advise and represent clients in patent matters on a professional basis, and if that person regularly acts as an opponent before the EPO in his own name, then he himself creates the impression that these activities in opposition proceedings are to be seen as part of his normal professional activities. This would justify investigating the question of his entitlement to act as an opponent. In the case, for example, of a patent attorney who is not authorised to act as a professional representative under Article 134 EPC and who is subject to some form of disciplinary supervision, the issue of entitlement could be clarified by requiring a statement to the effect that the opposition in question was not filed on behalf of a client.

6. The question then arises whether a relevant challenge to the admissibility of the opposition, as described in point 4, may be raised for the first time at the appeal stage. This question arises not only, as formulated in question 1 of the referral T 649/92, in cases where the challenge is raised by the patent proprietor; it is equally pertinent if the admissibility of the opposition is challenged by the EPO of its own motion.

The answer must be the same in both cases. A circumvention of the law in an abusive manner by the use of a straw man, which can be challenged as indicated in point 4, is not to be accepted at the appeal stage, even if no objection has been raised by the department of first instance. This is already established by the fact that a decision of the EPO on the validity of a patent requires the existence of an admissible opposition. This applies equally to proceedings before the board of appeal and the opposition division. Moreover, the public interest in preventing the above-mentioned inadmissible practices must take priority here over the need for efficiency in conducting the appeal proceedings. Since acting on behalf of a third party does not give cause to investigate the possibility of a circumvention of the law by abuse of process unless further particular circumstances are involved, the extra work entailed in appeal proceedings will in any case be strictly limited. Since the answer to question 1 in T 649/92 leads to the conclusion that an admissible challenge can still be raised without restriction in appeal proceedings, question 2 in T 649/92 does not arise.

7. According to point 5.3 of the Reasons in the referral decision T 649/92, question 5 is put to cover the possibility that the answers to the other questions might restrict the period during which a challenge to the admissibility of the opposition may be raised. The possibility of such restriction is rejected by the answer to question 1 of the referral T 649/92. In this sense, question 5 is therefore redundant.

However, question 5 itself is couched in broader terms which also comprise substantive restrictions on the right to challenge the admissibility of the opposition. The Board sees a need to address the question in this wider sense. The above answers to question 1 in T 301/95 and question 3 in T 649/92 do indeed involve a restriction, compared with previous case law, on the possible challenges to the admissibility of the opposition, since the fact that the opponent is acting on behalf of a third party does not as a rule lead to inadmissibility of the opposition. In the Board's view, however, the immediate application of the principles contained in its answers does not infringe any interests that deserve to be protected. A transitional rule is therefore unnecessary. Instead, it is sufficient to refer to the general rule that a decision of the Enlarged Board of Appeal is to be applied to all pending proceedings (G 9/93, supra, Reasons point 6.1).