Apple's phenomenal international success may all come down to one Irish woman, an accountant called Cathy Kearney. If Apple are legally  gaming the irish system and avoiding taxation in two jurisdictions then not so chatty Cathy who refuses all media requests is the key player.

According to the Daily Mail, as one of the heads of Apple's European operation the 49-year-old is a driving force behind the company's remarkable financial success.

An example of her nimble financial work can be seen in the fact that the County Cork based Apple satellite company she is director of reportedly earned $22 billion in 2011, but paid just $10 million in taxes.

But eye-popping profits on this scale are increasingly coming under the scrutiny of U.S. officials anxious to discover how the company has made so much money.

Apple reportedly uses five companies located in Ireland to carry out its global tax strategy, according to a 40-page report issued by the US Senate Permanent Subcommittee on Investigations.

The report, which led to Apple chief Tim Cook defending the company before a Senate panel last week, discovered that Apple employs a group of affiliate companies outside America to allegedly avoid paying tax.

The companies are located at the same address in Cork and they share members of their boards of directors - including Cathy Kearney - who has refused in the past to have her photo published. Although all five companies were incorporated in Ireland, only two of them also have tax residency there. This means the other three aren't legally required to pay taxes in Ireland because they aren't managed or controlled in that country. That means the company can legally shift its profits to different operations, which results in it paying less tax.

The subcommittee's report estimates that Apple avoided paying at least $3.5 billion in US taxes in 2011 and $9 billion in 2012 by using the tactic.

Apple's tax strategy has allegedly meant that the Cork-born accountant has had to answer U.S officials' questions about Apple's tax payments. Meanwhile Kearney's 'shrewd direction' was celebrated as one of the main reasons the company has enjoyed so much profit.

Meanwhile Apple is insisting it complies with the law and pays 'an extraordinary amount' of tax. In an earlier statement the computer giant said: 'Apple does not use tax gimmicks. And Apple pays all its required taxes, both in this country and abroad.'

The company has declined to make any further comment regarding Cathy Kearney's directorship.