Tim Cook has turned down an invitation to appear before the Irish parliamentary finance committee to offer his thoughts on the EU's ruling over Apple's tax affairs with the nation.

Last year, the European Commission ruled that tax arrangements between Ireland and Apple were in breach of the EU's state aid laws. It said the American corporation needed to cough up €13bn in back taxes, plus interest.

Although both nation and corporation have vowed to fight the ruling, Teachtaí Dála in the Oireachtas finance committee are prepping to give the government's activities their due scrutiny.

While the committee doesn't have the power to compel attendance of its sessions, its invitations have been accepted as a matter of course, until Apple CEO Tim Cook politely said no today.

According to the Irish Times, the committee received a letter this week from Apple exec Claire Thwaites, penned on behalf of Cook, saying that he had been advised not to appear.

Given the sensitive nature of the investigation and the timing, we have been advised not to undertake any other direct activities, which could potentially prejudice future outcomes. It is on this basis that we are unable to appear before the Committee on this occasion.

Sinn Féin's finance spokesman, Pearse Doherty, took to Twitter to share his displeasure at Cook's decision.

Disappointed and angry at Apple decision to refuse to attend Finance Committee. Legal excuse doesn't add up-others involved attending ! — Pearse Doherty (@PearseDoherty) January 5, 2017

Will push Committee to ask Apple to reconsider. Tim Cook attended Senate hearings & claimed a deal was in place. Dail deserves same respect — Pearse Doherty (@PearseDoherty) January 5, 2017

In a bit more length, and in an official capacity, Doherty said:

I am disappointed and angered by the decision of Mr Tim Cook not to attend the Committee. The EU's State Aid ruling has created a huge debate in this country about our tax affairs and it is only right the Finance Committee of the Oireachtas carry out hearings on this issue. Mr Cook appeared before the US Senate hearings and it was his comments there that sparked much of the discussion and possibly even EU action in this case. For him to refuse to attend the Committee now is disrespectful to the Irish people. He has also not been shy in speaking to Irish media about the case and his views on why the EU is wrong in its findings so the excuse of an ongoing legal case is not valid. After all both the Irish government and EU Commission are involved in that appeal and I expect both to attend the Committee. One would have thought Mr Cook would be keen to put Apple's view before the Irish people. I will push for the Finance Committee to write to Mr Cook requesting that he reconsider his position. I will also be pushing the Minister for Finance and the Taoiseach to make contact with Mr Cook and let him know that they believe an invitation by an Oireachtas Committee is important and that the government believes he should attend. When I first suggested, some years ago, inviting in multinational CEOs as part of a Committee investigation into Global Tax, I was voted down by Fianna Fail, Fine Gael and Labour. This time, there was unanimous political support for the invitation. It is all the more disappointing therefore that Mr Cook has refused.

Fianna Fáil Finance Spokesperson, Michael McGrath told The Register he was "very disappointed that Apple has decided, on legal advice, not to attend before the Oireachtas Finance Committee as I feel the company could have been of significant assistance in the Committee's examination of the European Commission's finding."

"Nonetheless, as far as I am concerned," McGrath continued, "the Committee has to continue with its work on this issue and will engage with all those who are willing to attend before the Committee. There is a great deal of information now in the public domain for us to assess. Commissioner Vestager has confirmed she will attend on behalf of the European Commission and I trust that the Revenue Commissioners will attend to put forward the State's case."

The Register has attempted to contact Apple, but received no response. ®