into confusion by a 10-day computer glitch.

The fault in the Bank of Butterfield system resulted in withdrawals and deposits being recorded twice on customers' accounts.

For a time, some people became "richer'' and others became "poorer'' than they really were.

The bank is now sending letters to up to 300 customers with their regular statements, telling them they have been affected and giving numbers to call.

Bank spokesman Mr. Wendell Emery assured customers yesterday: "The bank is confident that we have identified the problem and taken the neccessary steps to correct it.'' Mr. Emery, assistant general manager of retail banking, said people who used the bank's ATM machines from the afternoon of March 19 to the night of March 29 may have been affected.

The vast majority of transactions involved less than $100, he said. Current accounts were the ones mainly affected.

"We had a problem that caused some ATM transactions to be duplicated. If a customer made a withdrawal of $10, there were two debits to the current account for $10 as opposed to one.

"It affected a very small percentage of our customer base. It was just a programme glitch.

"It just sort of happened. It sometimes happens with computers and you never really get to the bottom of it.

"The letter was meant to try to explain it as simply as we could without getting technical.'' He said it was "probably unlikely'' customers did not have records of their machine transactions.

"If a customer did have a problem with an entry we are in a position to sort it out for them and give them a full and detailed explanation.'' Machine transactions are automatically filmed, he said, and this would help solve disputes.

This is the first time the bank's system of 13 machines had not worked normally, he said.

"Hopefully it will never do it again. But I guess with computers there's always a possibility.''