A number of Bank of Ireland customers have been advised that they may be able to force the bank to continue to provide them with trust services for a very low and outdated fee.

Many customers have taken legal advice following the revelation by the bank that it had been overcharging them - in some cases for many years.

A spokesman said yesterday most customers had been refunded the amount that was overcharged, together with interest. The bank will not disclose how many customers have been affected or the amount of money it has handed over.

The monies were paid out of a €22 million (£17.3 million) general provision made in the bank's balance sheet last year. The spokesman said the amount paid out was considerably less than had been provided for in the fund.

Some customers are continuing their discussions with the bank. These are primarily centred on their options for the future, which include accepting a significantly higher annual administrative fee. Other customers have moved their business elsewhere, while some have dissolved their trusts.

"The worst position for the bank would be that it would have to continue to handle a trust in an unprofitable way," said the spokesman, but added this was a very unlikely outcome.

The Irish Times has learned, however, that a number of customers have secured legal advice suggesting the bank should not be in a position to apply fees which are not provided for under the terms of their trust documents.

The fees charged are levied as a percentage of the total amount of assets governed by the trust. The assets held in this type of structure to be distributed on the death of the customer can be very substantial.

Bank of Ireland is the largest provider of trust services in the Republic. The business has undergone an intensive investigation following the overcharging revelations. The bank said the instances of overcharging were uncovered by its internal auditor on examination of trust deeds held at the bank.