The investigation was promised after the M&G uncovered a culture within the AU which, at its worst, "excludes and humiliates" women working there under a system of "professional apartheid".

African Union Commission chairman Moussa Faki Mahamat immediately promised a probe into the allegations, declaring he would not allow "discrimination against women under my watch".

That was three weeks ago, and now - with no evidence of an investigation getting underway - one employee told the paper's Simon Allison she feared any investigation would simply be "window dressing".

The AU did not respond to the M&G's request for comment.