NatWest have been struck by another technical blunder which has left some customers short-changed on their monthly interest payments.
Some NatWest and Royal Bank of Scotland (RBS) customers checking their E-Isa balances found they had been updated with just a few pence worth of interest in some cases.
A spokeswoman for RBS/NatWest described the error as an isolated incident and said customers' balances are being updated with the correct amounts as a matter of urgency.
Those who have found a mistake do not need to contact the bank as it will be automatically fixed.
While this latest failure is not IT-related, the bank has been beset by a string of technological errors in recent months.
Just days after that incident, the bank's websites were the victim of a cyber attack that left some customers unable to access their accounts.