The European Commission’s competition arm conducted a sweep of the tax files of several hundred multinational companies on a visit to Dublin last year.

The move came as the commission was in the midst of its investigation into Apple’s tax affairs.

The commission’s examination of the Revenue files does not appear to have led to any follow-up inquiries with the authorities or any of the companies concerned, but is a further sign of its active interest in the area.

Sources here say the European Commission has been investigating only one case in Ireland – Apple.

The visit by the commission’s competition arm did not come to light at the time.

It is believed to have examined the files of some 300 companies and to have received full co-operation from the Irish authorities.

The commission made its preliminary ruling that Ireland had provided illegal state aid to Apple in 2014.

Tax advisers are awaiting publication of the detailed judgment from the European Commission, but point out that its conclusions inevitably focus on Apple’s specific arrangements here.

Apple reached an agreement with Revenue on how revenues would be divided within Irish-registered companies and its moving of these funds through companies with no tax residency here is thought to have been unusual.

Direct interference

Business groups broadly welcome the Government’s decision to appeal against the commission’s findings.

ICT Ireland, which represents many technology companies, said it was important to get certainty via the European courts.

Chambers Ireland said it represented direct interference in the tax affairs of a member state.

The decision to appeal was also welcomed by IDA Ireland. Chief executive Martin Shanahan said: "The prospect of the commission retrospectively rewriting Irish tax rules is not acceptable to Ireland."

He said the decision was unhelpful for attracting foreign direct investment into Europe.