The resignation was received prior to his second disciplinary hearing, which was to be held in Sandton on Friday morning.
In the letter Koko said “I do so without any admission of wrongdoing,” adding that he has “good defences to these charges that have been conveyed to Eskom’s legal representatives”.
Koko had previously appeared before a parliamentary portfolio committee on public enterprises where he lied about his association with the Gupta family who were named in the former public protector Thuli Madonsela’s State of Capture report. He also failed to reveal that his trip to Dubai was paid for by the Guptas.
Koko, at the time, was adamant that he would not resign as he still had a role to play at Eskom.