In T 227/92 it was held that a sub-authorisation from a professional representative to a person who was not a professional representative within the meaning of Art. 134 EPC 1973 was invalid. The latter person's role was therefore limited to that of technical adviser to the professional representative.
In T 382/03 the previous representative, Mr E. of UDL, filed a fax to announce that Mr U., who was not a member of that association, would appear for respondent 1 at the oral proceedings before the board. Mr E. did not notify the board that his association's authorisation was terminating. Hence, that was a situation where the President's decision required the new representative, Mr U., to prove that he was authorised to act on behalf of respondent 1. As Mr U. did not refer to a general authorisation from respondent 1, proof of an individual authorisation had to be provided to the board. In principle, that could be done by filing a direct individual authorisation from opponent 1, or by filing a sub-authorisation from an authorised representative who was entitled to sub-authorise a third representative. In view of the sub-authorisation from UDL submitted by Mr U. at the oral proceedings, the only issue remaining was whether or not UDL was entitled to give such a sub-authorisation. As Mr G. had filed notice of opposition 1 without filing an authorisation, there was no evidence on file that Mr G. had obtained the power to give sub-authorisations. In the board's view, the issue of whether or not a board considers a representative to be authorised by a party was a matter of proof including a free evaluation of the evidence and overall circumstances in an individual case. To define an appropriate standard of proof with respect to a representative's authorisation, the board took account of the purpose for requiring an authorisation.
For an example of a professional representative entitled by a chain of sub-authorisations to make submissions on behalf a party, see T 1081/06.