The Tánaiste, Ms Harney, said yesterday her decision three-and-a-half years ago to investigate Dunnes Stores had been vindicated by the Supreme Court.

Ms Harney said the court's ruling that she was entitled to appoint an authorised officer to two Dunnes Stores group companies meant she "was right in the decision that I took that I was not acting improperly as was suggested".

She said she was anxious the inquiry would now take place, and said it was a pity it had taken so long. Responsibility for progressing the inquiry rests with the recently established Director of Corporate Enforcement.

Mr Paul Appleby, the director, said yesterday he would have to take legal advice before deciding how to proceed. He may have to await the resolution of a number of constitutional issues, which were raised by Dunnes Stores but not dealt with by the Supreme Court.

It is still open to Dunnes Stores to ask the High Court to rule on this part of its challenge to the Tánaiste. The constitutional issues were effectively parked by the High Court in June 2000. Mr Appleby is not expected to proceed until Dunnes Stores indicate their course of action.

The Tánaiste seemed oblivious to the possibility of further delay yesterday. "We had a long legal process and I am delighted now with the decision of the Supreme Court," she said.

The High Court decision, which went "very much against us" had been a serious concern, she added.

"I was determined, given the legal advice that we had, given the fact that I was acting under the legislation based on legal advice, that we were right," she said.

"So we wanted clearly to challenge the decision and appeal the decision to the High Court and I am now delighted that the Supreme Court has vindicated the stands we took.

"I am sorry, of course, that it has taken so long to get to this point, but the legal process can often be very slow," she said.