In J 19/89 (OJ 1991, 425) the Legal Board of Appeal considered whether a patent attorney under national law should, in view of his legal qualifications and entitlement to act as a professional representative in national patent matters, be regarded as a "legal practitioner" within the meaning of Art. 134(7) EPC 1973 and hence be authorised to act before the EPO. The board decided that irrespective of his specialist qualifications and powers of representation in national patent matters, a patent attorney under national law could not be regarded as a "legal practitioner" within the meaning of Art. 134(7) EPC 1973, and therefore was not entitled to act as a professional representative before the EPO (see also D 14/93, OJ 1997, 561).

In T 643/01 the appellant (patent proprietor) contended in particular that the opponent's reply of 28 January 2002 was inadmissible on the ground that it had been signed by Mr R., who was a legal practitioner and member of the Paris Bar but who was allegedly unable to show that he possessed an authorisation conforming to the requirements of R. 101(1) EPC 1973. The appellant requested that, if the signatory concerned was relying on his official status as a professional representative before the EPO, the board should find that French law prohibited such a plurality of offices, since the exercise of the profession of barrister could not properly be combined simultaneously with that of industrial property attorney. The board held, in the case at issue, that the signatory of the impugned pleadings of 28 January 2002 was entitled to act before the EPO and held the appropriate authorisation for that purpose. Mr R. and Mr D., legal practitioners and members of a partnership, were indeed members of the Paris Bar, and the names of both appeared on the list of professional representatives before the EPO. They were therefore both entitled to act in one capacity or the other before the EPO under Art. 134(1) and (7) EPC 1973. The board held that a decision on the legality, in France, of simultaneously exercising the profession of barrister and acting as a professional representative before the EPO fell solely within the jurisdiction of French professional and judicial bodies.

In J 27/95, the Legal Board of Appeal first made it clear that the competence of legal practitioners to undertake representation before the EPO depended directly on their complying with the provisions of Art. 134(7) EPC 1973. Thus, each time a legal practitioner made a request to act as a professional representative in proceedings before the EPO, the Legal Division had the right to examine whether he or she satisfied the conditions under Art. 134(7) EPC 1973. In its decision the board pointed out that a legal practitioner qualified in a contracting state had to have "his place of business in such State". The place of business within the meaning of Art. 134(7) EPC 1973 was the place (if any) at which a person practised his or her profession as legal practitioner.

In T 1846/11 the board considered the legal consequences that would ensue if there was no authorisation filed for a legal practitioner, or any subsequent approval by the appellant submitted for steps taken by a legal practitioner without such authorisation. Mr K. was a legal practitioner entitled to act as a representative under Art. 134(8) EPC. A legal practitioner must file the original version of a signed authorisation or a reference to a general authorisation already on file under R. 152(1) EPC and Art. 2, first sentence, of the Decision of the President (OJ SE 3/2007, 128). Mr K. filed a duly signed general authorisation from the appellant dated 8 April 2016. The board was satisfied that this general authorisation authorised Mr K. to represent the appellant in proceedings before the EPO and thus in the present appeal proceedings as from 8 April 2016. However, since the general authorisation was dated 8 April 2016, any procedural steps taken by Mr K. as representative up to that date were not covered by that authorisation itself. The board would exceptionally have accepted that the appellant subsequently approve the procedural steps taken by Mr K. as representative in the period from 1 October 2010 to 8 April 2016. However, Mr K. failed to file any such approval. The legal consequence was that the procedural steps taken by Mr K. were deemed not to have been taken (R. 152(6) EPC applied mutatis mutandis). Consequently the notice of appeal was deemed not to have been filed and an appeal did not exist.

In J 35/92 the first-named of two individual joint applicants had transferred his rights in the application to a company, which had appointed another representative who had then purportedly withdrawn the application. The second applicant did not agree with the withdrawal. The department of first instance held that the company was entitled unilaterally to withdraw the application by virtue of R. 100(1) EPC 1973, according to which the first-named applicant could be regarded as the representative of both, but the board of appeal disagreed. R. 100 EPC 1973 applied only where no joint professional representative had been appointed, whereas in the case in question the original applicants had appointed a representative, who continued to act for the second applicant. The board therefore concluded that the purported withdrawal of the application by the first-named applicant was invalid. The parties were given two months to appoint a joint professional representative, failing which one would be appointed by the EPO.

In J 10/96 the Legal Board of Appeal ruled that where several applicants were represented jointly by a professional representative, who during the course of proceedings ceased to represent his clients, the correct procedure to be followed was that contained in R. 100(2), second sentence, EPC 1973, according to which the applicants were to be requested by the EPO to appoint a common representative within two months. If this request was not complied with, the EPO was empowered to appoint the common representative.

In G 3/99 (OJ 2002, 347) the Enlarged Board of Appeal dealt with the question of the admissibility of joint oppositions and joint appeals. The decision makes it clear that an opposition filed in common, apart from the fact that it is filed by more than one person, is as much a single opposition as an opposition filed by only one person. In an opposition filed in common, there must in all cases be a common representative (Art. 133(4) and R. 100 EPC 1973), and only that common representative is entitled to act in the opposition proceedings on behalf of all the common opponents taken as a whole.

The decision further notes that an individual common opponent not being the common representative, or a subgroup of the group who filed the opposition in common, but without their common representative, is not allowed to act or intervene on his own or on behalf of one or more or all of the other individuals. Thus, only the common representative is entitled to sign the filed documents (R. 100 and R. 36(3) EPC 1973), the signature of other individuals not being required. At any stage of the procedure, be it the opposition or the appeal procedure, it may also occur that the joint member who is the common representative intends to withdraw from being a joint member, i.e. to withdraw from the proceedings. In such circumstances, he must notify his decision to the EPO with the procedural consequence that, for the determination of a new common representative, the provisions of R. 100(1) EPC 1973 have to be applied for the opposition procedure by virtue of the last sentence of that rule and, for the subsequent appeal procedure, by virtue of R. 66(1) EPC 1973.

It may also occur that the common representative ceases to act in the procedure without the EPO being informed thereof. In both cases, the other joint members must take the appropriate action to continue the procedure in due time and to inform the EPO of the new common representative, if appointed. However, there is no practical need to acknowledge the validity of procedural acts of a joint member who is not the common representative. Since a procedural act performed by a non-entitled person is treated by the EPO in the same way as a missing signature (see T 665/89), each joint member or any other person acting on his behalf can perform such an act to avoid missing a time limit, provided the deficiency is remedied within a further time limit set by the board in the communication under R. 36(3) EPC 1973 notified to the common representative and sent for information to the non-entitled person who performed the act. The deficiency can be remedied if the procedural act is signed by the common representative.

G 3/99 was applied in T 1154/06 in connection with the necessity of appointing a professional representative if the first-named of multiple patent proprietors was not resident in a contracting state. (See R 18/09, in which the Enlarged Board referred to these two decisions and held that both the principle that a plurality of persons acting in common must be treated as a single party (a "group party") and the requirement that such a group party acts through a common representative apply to petition proceedings.)

In T 1654/13 it was submitted that the appeal filed by the common representative of the joint patent proprietors had to be understood as having been filed on behalf of both patent proprietors as joint appellants. The wording used in the notice of appeal, referring only to the first of the two patent proprietors, i.e. Unilever N.V., thus had to be understood only in relation to the request for the reduction of the appeal fee. The board, citing Art. 118 EPC and calling to mind R 18/09 and T 1154/06, decided that there was no doubt that Unilever N.V. and Unilever PLC were joint appellants. The appeal was admissible.

In decision T 1366/04 the appeal had been filed by the first of two joint patent proprietors only. The board held that the requirements of Art. 118 EPC were met and that there was no doubt about the identity and appellant status of the two patent proprietors.

Decision T 418/07 concerns a different case, where shortly before the oral proceedings the respondent (patent proprietor) appointed a second firm of representatives as joint representatives in addition to the firm already acting and asked the board to send copies of all correspondence to both firms. In this case of multiple representatives, the board held that while it is open to a party to appoint as many representatives as it may wish, the board is not aware of any requirement on it or on other parties to send correspondence to more than one representative of one party. If a party wants to retain multiple representatives, it must make its own arrangements for copying correspondence to them all. Parties cannot expect the board to provide copying services for their convenience.