Manchester City will launch an investigation into an email sent by chief executive Garry Cook.

City defender Nedum Onuoha's ill mother, Dr Anthonia, received an email from Cook when she, acting as her sons agent, was in negotiations with club football officer Brian Marwood and Cook over a contract.

Cook has since denied sending the email to Dr Onuoha, which mocked her being 'ravaged with cancer' saying he was away at the time and somebody hacked his computer but nonetheless, a full enquiry will go ahead.

"Following allegations made to the football club by Dr Anthonia Onuoha, subsequently reported in today's media, the club can confirm that a board-led review has been launched into the matter," said a City statement released on Monday evening.

Dr Onuoha was being treated for cancer when the email was received and she admits it was one of the worse days she can ever remember.

"When I opened up my e-mails and saw the message, it was the worst day of my life, even worse than being diagnosed with cancer," she told The Sun.

"I couldn't understand how anybody could behave like that. I just cried and cried for hours.

"I'm critically ill and at that point I was undergoing chemotherapy. I was just so shocked but I couldn't tell Nedum or any of my family because I didn't know how they would react.

"It's incredible that any human being would write this. It's unforgivable and I still cannot believe it."