When the McCracken tribunal publicised the existence of the dodgy Ansbacher accounts earlier this year and the role played in their management by the Guinness & Mahon (Ireland) Bank, the response from Dame Street was a deafening silence.

The only comment from the Central Bank was that the work of Mr Justice McCracken was being monitored. There was no hint of concern that its own banking regulations appeared to have been systematically flouted. There was no comment on the breaching of exchange controls.

The Central Bank appeared to be unaccountable for its actions or its lack of them. It wrapped its operations in a veil of secrecy and took refuge in the shadow of the Government.

The utter darkness of that shadow quickly became apparent when Fianna Fail and the Progressive Democrats decided not to investigate the legality and ownership of £38 million in the Ansbacher accounts, under the terms of reference of the newly appointed Moriarty tribunal. Only payments made to Ministers or to public servants from those accounts would be examined. Everything else would be ignored.

Having effectively countenanced the use of the Ansbacher accounts for tax-evasion purposes, it was only a small step for the Government to discount breaches in exchange controls. The duties and responsibilities of the Central Bank, as agent for the Minister for Finance, would be conveniently overlooked. It had all the makings of a snow-job.

However, it didn't quite work out like that. A bland request by Charlie McCreevy for the bank to review its operations in the light of the McCracken report generated a flurry of activity. A report on possible breaches of exchange controls caused the Minister for Finance initially to refer the matter to the Attorney General for legal advice rather than publish the document.

An addendum caused both documents to be sent straight to the Director of Public Prosecutions. In addition, the Minister forwarded the documents to the Moriarty tribunal, dealing with payments made by Ben Dunne to Charles Haughey and Michael Lowry. And he sent them to the Revenue Commissioners for further exploration.

An element of panic appeared to be abroad. Mr McCreevy sought additional relevant information from the Central Bank on exchange controls and crucially, he asked whether the bank felt it had the necessary powers to undertake its regulatory role.

That latter action had the appearance of a fire-brigade response. The terms of reference of the Moriarty tribunal require it to make broad recommendations "for enhancing the role and performance of the Central Bank as a regulator of the banks and of the financial services sector generally". The Minister was inviting the Central Bank to engage in a pre-emptive strike.

Like the dog that didn't bark in the night, the Central Bank made no comment on pivotal issues, which included its supervision of Guinness & Mahon in Dublin and, in particular, whether it questioned the large amounts of money deposited in the Ansbacher accounts.

Banks such as Guinness & Mahon are authorised to trade by the Central Bank and can have their licences withdrawn if they don't obey regulations. Among those regulation is a requirement that a bank shall not owe more than 15 per cent of total deposits to any one interbank depositor or what is deemed by the bank to be an associated group of interbank depositors.

The late Des Traynor, who had control of Charles Haughey's financial affairs from the early 1960s, was appointed a director of Guinness & Mahon in 1969 and became de facto chief executive in 1976. He set up a small Cayman bank in 1969 and in 1974 he became chairman of Ansbacher Cayman Ltd.

Initially, Mr Traynor had total control of the Ansbacher accounts, deposited with Guinness & Mahon and, by 1989, they amounted to £38 million. The McCracken tribunal suggested that, in some instances at least, the mechanisms were designed to evade tax.

Mr Traynor left Guinness & Mahon in 1986. In the following year, its auditor reported he was "very unhappy with the situation" in relation to the Ansbacher accounts. A further audit conducted in 1989 expressed "particular concern" over what was going on. It concluded: "Lack of internal control over this activity coupled with the fact that the Ansbacher deposits constitute nearly 35 per cent of the bank's liabilities, expose the bank to serious risks of loss and embarrassment.

"These risks together with the legal position of the bank vis-a-vis the maintenance of offshore customer deposits by a bank employee and on the bank's premises need to be evaluated by the board."

These comments, published in the McCracken report, raise questions about the role and the effectiveness of the Central Bank. The bank conducts a combination of off-site surveillance and on-site inspections, involving an inspection of detailed returns, of bank books and records. There are also regular review meetings with senior management.

In those circumstances and given the internal audits conducted by Guinness & Mahon, it would stretch credulity to believe the Central Bank did not know what was going on.

The questions which remain to be answered are: what did the Central Bank do with that information; did it impose sanctions; did it report to the Minister for Finance and with what result; was it aware of tax evasion and did it apply its own banking rules?

Given its track record for secrecy, the Central Bank is not expected to come out with its hands up, but the Moriarty tribunal is in a position to ask those questions because of its brief to report on the adequacy of Central Bank powers and procedures. The legal representative of the public interest at the tribunal will have plenty to do.