The parliamentary inquiry into corporate governance at Eskom resumes on Monday.
With government ringing in the changes, the presidency has instructed the newly announced Eskom board to immediately remove all executives who are facing allegations of serious corruption, including Singh and Koko.
Koko was recently cleared in an internal disciplinary process after allegations that he had not declared a conflict of interest while his stepdaughter was a director at a firm which benefited from about a billion rand worth of contracts awarded by Eskom.
Singh has been accused by several witnesses of advancing the business interests of the Gupta family at Eskom.
He is said to have been central in securing R659 million prepayment by Eskom to a Gupta owned company, Tegeta, which allowed it to buy a coal mine and obtain a lucrative supply contract with Eskom.
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