Did Man City cook the books to avoid Financial Fair Play penalties?

Manchester City have been accused of cheating after claims that their owner paid large parts of inflated sponsorship deals himself.

According to a  batch of alleged  hacked emails by whistle blowers Football Leaks reported in Der Spiegel, claims have been made that Sheikh Mansour picked up the tab for large parts of agreements with club sponsors as part of attempts by City officials to comply with Uefa's Financial Fair Play (FFP) regulations.

Doubts over the authenticity of the deals, with companies based in the Sheikh's Abu Dhabi homeland, have long been raised - and, if proved to be genuine, a series of messages suggests all may not be as it seems.

In 2010, one of the allegedly hacked emails reportedly from board member Simon Pearce, communicating with bosses, allegedly discusses a £15m deal with partner Aabar. 'As we discussed, the annual direct obligation for Aabar is £3m,' he allegedly wrote. 'The remaining £12m requirement will come from alternative sources provided by His Highness.'

Der Spiegel say that single sentence confirms accusations that Sheikh Mansour personally paid a portion of sponsorship money.

In another allegedly hacked message, City's chief financial officer, Jorge Chumillas, allegedly wrote that the club was facing a £9.9m shortfall to comply with FFP thanks to the contract termination of sacked former manager Roberto Mancini.

Mancini was sacked in 2013, a year to the day after winning the Premier League title. His giant pay-off meant yet more expenditure on City's books that had to be covered by income under UEFA rules.

He adds: 'I think that the only solution left would be an additional amount of AD (Abu Dhabi) sponsorship revenues that covers this gap.'

According to the report, Chumillas goes on to suggest sponsors Etihad pay an extra £1.5m, Aabar £0.5m and the tourism authority £5.5m.

Financial Fair Play was approved by UEFA in 2010 and first brought into play in 2011. It ensures that clubs who have qualified for UEFA competitions must prove they do not have overdue payables towards other clubs, their players and tax authorities throughout the season.

In short, clubs can spend up to €5m (£3.9m) more than they earn per assessment period, although total losses of £35m are permitted for clubs like City with the wealthiest of owners.

In a further reported email exchange, it is alleged Chumillas asks Pearce if they can change the date of payment from Abu Dhabi sponsors. Pearce responds: 'Of course, we can do what we want.'

Der Spiegel go on to allege that City's financial reports are 'a web of lies'. They say that in another email Pearce allegedly writes that stadium and jersey sponsor Etihad Airways 'direct contribution remains at a constant £8m' which does not appear to tally with the actual obligation of £35m.

The publication claims that annually, the deal was worth £67.5m but say that Chumillas is alleged to have written  to Pearce: 'Please note that out of those £67.5m, £8m should be funded directly by Etihad and 59.5 by ADUG.' ADUG stands for the Abu Dhabi United Group – City's ownership vehicle.

When contacted for a response, Etihad told Der Spiegel that the financial obligations associated with the partnership with the club have always been and remain the airline's 'sole liability and responsibility'. Aabar and the Abu Dhabi tourism authority reportedly did not respond to the specifics of questions.

The report ends by alleging that internal City calculations noted that by May 2012, when the club won the Premier League, a total of £127.5m had been used to supplement Abu Dhabi partnership deals.

When contacted by Sportsmail, City referred to an earlier statement, which reads: 'We will not be providing any comment on out of context materials purportedly hacked or stolen from City Football Group and Man City personnel and associated people. The attempt to damage the club's reputation is organised and clear.'