Tarnished reputation tainted further, writes Arthur Beesley, Senior Business Correspondent

The conclusion of the inquiries into overcharging at AIB adds a further €31.6 million to its liability from the scandal, bringing the grand total to €65.8 million. But the damage to Ireland's largest bank doesn't stop there.

We know now that the bank's customers were overcharged as far back as the 1980s, further tainting the already-tarnished reputation of the most powerful financial institution in the State.

The bank that survived the ICI and DIRT debacles, Rusnak and the Faldor affair expressed regret yet again for its failings yesterday and chief executive Eugene Sheehy spoke of "valuable lessons learned". But for all his apologies, not a single official or manager will be disciplined.

AIB concluded "in view of the lack of evidence, due principally to the passage of time" that it could not sanction staff. The bank's statement yesterday deals with an internal investigation into issues uncovered but not examined in detail by the 2004 inquiry overseen by the Irish Financial Services Regulatory Authority into foreign exchange overcharging.

In that instance, the regulator found that certain staff and management in AIB deliberately hid the fact that thousands of foreign exchange customers had been overcharged to the tune of €34.2 million for more than eight years.

At the time, it was suggested in private that up to 10 senior managers in AIB were facing disciplinary proceedings. This cannot be verified because the bank won't discuss its internal disciplinary process. One manager, Séamus Sheerin, fought his dismissal from the bank in the High Court. Mr Sheerin resigned after an out-of-court settlement that meant AIB avoided a public airing of potentially damaging claims that he had made against the bank.

The latest investigation, overseen by former Central Bank governor Maurice O'Connell, dealt with certain foreign exchange transactions in the early 1990s and interest overcharging elsewhere which arose in the 1980s.

On foreign exchange, the bank said that €10.5 million was overcharged due due to the application of "incorrect margins" in various situations in before 1995. "Records do not enable the identification of customers affected by these issues and so a payment of €17.3 million, to include interest of €7.3 million, to compensate for the passage of time, will be made to charity."

Some €11 million is to repaid to customers as a result of the examination of other overcharging cases. The biggest refunds - totalling €4.6 million - will be made in respect of payment protection insurance. A further 29 unspecified charging errors will result in refunds of €2.7 million.

In addition, customers stand to receive €1.4 million due from the early terminations of lease contracts and €1 million for the inconsistent application of affinity schemes on certain products. Some €700,000 is due for stamp duty wrongly collected on ATM and Laser cards.

A further €600,000 is due to customers of AIB's branches in O'Connell Street, Waterford, and Tramore, Co Waterford. "Following an investigation of the branch network, the bank found no evidence of a wider incidence of the application of incorrect interest charges as identified in Tramore/Waterford."

Mr Sheehy said the bank was satisfied that the investigations are now complete. AIB had put new systems in place to ensure that its customers receive "the levels of transparency and service which they were fully entitled to expect at all times".

For customers - and indeed investors - the question naturally arises as to why no disciplinary action is being taken. When it was suggested that the failure to sanction staff was at odds with the highest standards of corporate governance, AIB's spokeswoman referred to the elapse of time since the 1980s and 1990s. "What's not possible to discover is whether these things were done mistakenly or wilfully. The evidence simply isn't there."

By contrast, evidence did emerge in the 2004 investigation that certain managers in AIB were aware of the overcharging problem. Indeed, Mr Sheehy's predecessor Michael Buckley said that managers failed to report the findings of a 2002 memo that quantified the problem and recommended bringing it to the attention of the regulator. Mr Buckley said the document wasn't even circulated to his senior management team.

Neither AIB nor the regulator will discuss the disciplinary process, so we do not know whether anyone was ever punished for their failure to bring that memo "up the line".

So, while there was overcharging in three decades at AIB, it appears that only Mr Sheerin lost his job. Banks are supposed to protect customers' money, not deprive them of their cash through overcharging. AIB overlooked that basic principle time and time again.