The European Commission will today find that Apple owes the Irish State "billions of euro" in back taxes when it rules that the technology giant's tax arrangements in Ireland constituted a form of illegal state aid.

The amount of tax the commission will say that Apple owes the Irish exchequer is much larger than the amounts recently anticipated by the Government.

It is likely to lead to significant political pressure on the Government, which has made clear its determination to fight the ruling and so avoid receiving the massive tax windfall.

The ruling, to be announced in Brussels today, will not stipulate a figure for the amount of tax owed, but will lay out a process and a formula by which the unpaid tax should be calculated.

Indicative figure

It is expected an indicative figure will be supplied by the commission later in the day. However, the Government will appeal the commission’s finding, and says the money – though Apple may be required to pay the funds into an escrow account in the coming months – will not be available to spend, either now or in the future.

“They are making up new rules for international tax,” said one Minister last night. “They are trying to make us tax Apple for stuff that doesn’t happen here. It’s nonsense.”