The findings of two inquiries into the allegations of fee and interest loading by National Irish Bank, released yesterday, justify conclusions both in the bank's favour and against the bank.

Firstly, the allegation of improper interest charges as first alleged by RTE in March has now been shown to be of substance. Some £131,166 plus interest is to be returned to some 370 customers, averaging just over £350 per customer. This is a huge embarrassment for the bank.

On the other hand, if these figures properly represent the scale of the practice, then the contention that the money was taken from the customers' accounts so as to boost both profits and the careers of those involved seems hard to justify. Pre-tax profits at NIB in the six months to the end of March were £16 million.

The "anecdotal" evidence, according to NIB chief executive, Mr Grahame Savage, is that in many cases the charges were justifiable but were imposed as interest rather than fees in the hope that the customers would not notice them. He had no explanation as to how the practice came to exist in a specific number of branches and not in others.

The practice seems to have been concentrated in five branches: Carndonagh, Co Donegal; Carrick-on-Shannon, Co Leitrim; Cork; Walkinstown, Dublin; and Blanchardstown, Dublin. It is known that in May 1990, the then chief executive Mr Jim Lacey, wrote to Carrick-on-Shannon expressing concern about the imposition of increased interest charges and saying the practice must cease immediately.

In July 1990, Walkinstown informed a senior executive that it had ended the practice of interest loading.

Yet the Blanchardstown branch of NIB was opened in February 1991 and the practice of interest loading introduced there. How this happened has yet to be explained by the bank.

RTE made allegations about the bank in March and NIB chose to ask Arthur Andersen to investigate precisely these allegations. Consequently, the Arthur Andersen report only examines interest amendments for Carndonagh for the period October 1987 to December 1990; Carrick-on-Shannon for October 1987 to December 1990; Cork for January 1988 to December 1990; Walkinstown for January 1989 to December 1990; and Blanchardstown for the period February 1991 to May 1993.

That investigation found problems with interest charges in less than five other branches, involving a figure of £34,816 in all.