Cook battling to keep job after offensive email angers owners

Claim by Manchester City chief that mocking message was result of hacking is under investigation by officials

Garry Cook is being investigated by representatives of Sheikh Mansour for whom the email is a source of profound embarrassment (GETTY IMAGES)

The Manchester City chief executive, Garry Cook, was struggling to hold on to his job last night as the club's Abu Dhabi owners sought answers about an email sent from his account to the mother of defender Nedum Onuoha, mocking her fight against cancer.

Cook's claim, to Dr Anthonia Onuoha, that a member of City's staff had hacked into his email account on his iPad and sent the message as a joke, is being subjected to stringent investigation by representatives of Sheikh Mansour bin Zayed al-Nahyan, for whom the offensive email is a source of profound embarrassment.

The owners – whose attempts to make contact with Cook have been complicated by his presence in Portland, Oregon, with his American wife – want to know that Cook has not attempted to cover up an offensive email. The club confirmed in a statement last night that a "board review" into the incident had been launched. The review is expected to be brief but the prospects for Cook do not look good. A defence of the chief executive was conspicuous by its absence last night, more than 24 hours after City had become aware that the excruciating email, which was intended for Brian Marwood, City's football administrator, had been made public – nearly a year after it was sent.

Despite a series of high-profile gaffes, Cook had retained the support of his chairman, Khaldoon al-Mubarak, and is considered by the sheikh's representatives to be something of a commercial visionary with an ability to apply untried methods to football, imported from the Nike corporation where he first worked with Marwood.

But Cook's £1.5m-plus position will be considerably graver if he cannot demonstrate that he has not compounded an initial defence with a deceit. By his version of events, related via Dr Onuoha, someone would have had to have hacked into his computer and presumably discovered her email to him before sending a reply, addressed "Brian", to Dr Onuoha instead.

Ironically, City had gone to some lengths to appease Dr Onuoha during months of difficult contractual negotiations relating to her 24-year-old son. There had been strict attempts to prevent details of the discussions leaking out, in the knowledge that she would not respond well. But if Cook does lose his job, senior staff at City – who question how and why the details of the email exchange have leaked out now – will bitterly consider it to represent a triumph for the agent Kia Joorabchian, who also represents Onuoha and who has been at loggerheads with Cook for nearly three years. City notified the Football Association this summer when they were dismayed to discover that Joorabchian, who is not a registered agent, had a mandate to represent Onuoha.

Joorabchian's desperately poor relationship with Cook has been compounded by the on-off transfer saga of the club's £250,000-a-week striker Carlos Tevez. The dispute between Joorabchian and Cook dates to January 2009, when Joorabchian says Cook cut him out of negotiations to bring Kaka from Milan, thus scuppering the deal. On at least one occasion this year, Cook is said to have been been unwilling to remain in Joorabchian's company when he entered a room.

Cook's position had been under no threat until details of emails to and from Onuoha's mother, who has a doctorate in environmental sciences, emerged. She said in an email to Cook and Marwood last October that, although her body was "ravaged with cancer and ongoing chemotherapy", she still had her wits about her to argue Nedum's case. Two weeks later, she received the email addressed to "Brian", sent from Cook's address, which stated: "Ravaged with it!!......I don't now how you sleep at night. You used to be such a nice man when I worked with you at nike. G." Though Dr Onuoha demanded yesterday that the FA or the Premier League intervene, both organisations consider this to be an issue for her and the club to resolve.

City are weighing up whether Cook's position remains tenable. They have always known he is a liability in public but thought they had resolved that problem. Cook's effective disappearance from public view dates to his boast in New York's Mad Hatter Saloon last year that City would get to Wembley "not if, but when, we beat United again". The sheikh's representatives blamed the embarrassment on a lack of staff back-up to ensure the private function was not recorded. The Mad Hatter bar incident was one of many gaffes which have littered his three years at City.