The case law concerning due care on the part of professional representatives' assistants was established in J 5/80 (OJ 1981, 343). This key ruling by the Legal Board of Appeal lays down that a request for re-establishment of rights can be acceded to in the event of a culpable error on the part of the assistant, if the professional representative is able to show that he has chosen for the work a suitable person properly instructed in the tasks to be performed, and that he has himself exercised reasonable supervision over the work (see also T 191/82, OJ 1985, 189; T 105/85, T 110/85, OJ 1987, 157; T 11/87, T 176/91, T 221/04, T 1149/11).
Where an assistant has been entrusted with carrying out routine tasks such as typing, posting letters and noting time limits, the same strict standard of care is not expected as is demanded of the representative himself (J 16/82, OJ 1983, 262; J 33/90, J 26/92, T 221/04 and T 43/96). Decision J 5/80 also pointed out that, if other than routine tasks are delegated which normally would fall to the representative by virtue of his professional qualification, the representative would not be able to establish that he exercised all due care (see also J 33/90 and T 715/91). More recent decisions stress that responsibility in every respect passes to the representative as soon as he is presented with the file for processing, and that to that extent he is not justified in relying on an assistant's calculation of a time limit (see point (e) below).
Regarding the burden of proof in the form of an adequately detailed statement in connection with the duty of care in the selection, instruction and supervision of assistants, see J 18/98.