Manchester City chief executive Garry Cook resigned from his position at the club on Friday following claims that he sent an offensive email to the mother and agent of defender Nedum Onuoha.

Cook initially claimed that his email had been hacked into, but later admitted poor judgement on his part.

Dr. Anthonia Onuoha first sent an email to City's football administrator, Brian Marwood, last year, stating that despite the fact that she was "ravaged with cancer", she would still hold talks regarding her son's contract.

A few weeks later, Dr. Onuoha said she received an email from Cook that was addressed to Marwood, saying: "Ravaged with it!!......I don't know how you sleep at night. You used to be such a nice man when I worked with you at Nike (sic)."

City launched an investigation into the incident on Monday, and found that the allegations had merit, causing Cook to offer his resignation.

A statement from City on Friday read: "The club can confirm that there is foundation to Dr. Onuoha's allegations and the Chairman has written to apologize to Dr. Onuoha for any distress caused.

"Following the findings of the review, chief executive officer Garry Cook has offered his resignation, which has been accepted with regret by the board."