Michael Fingleton has been ordered to pay the full costs of his failed legal action against the Central Bank, which could be up to €500,000.

The former Chief Executive of Irish Nationwide tried to get the High Court to stop an inquiry into alleged regulatory breaches at the building society.

Michael Fingleton is accused of participating in the commission of some or all breaches of regulation at Irish Nationwide between 2004 and 2008.

The former Chief Executive claimed the inquiry was "unfair and unreasonable", and in an affidavit sworn from Marbella in Spain, he said it would be hard to defend properly because his financial position is "by no means strong".

He also argued that the Central Bank was acting outside its powers because he is no longer involved in the management of a regulated entity – a point raised again during a costs hearing today.

His counsel claimed it was in the public interest to clarify this section of the law and asked the court to depart from its usual position, whereby costs are awarded to the successful party.

However, Mr. Justice Seamus Noonan decided against him, ruling that his action was solely concerned with his private interest.