When a transaction would exceed the previously agreed overdraft limit the bank can choose either to decline the transaction or to accept it as an informal request for an increase, formerly often known as an unauthorized overdraft. Charges and interest rates for informal increases will often exceed those for a formal request. There is also normally a fee per declined transaction, often subject to monthly caps. Usually, the bank sends out a letter informing the customer of the charge and requesting that the account be operated within its limits from that point onwards or informing the customer of their new limit. In a BBC "Whistleblower" programme on the practice, it was noted that the actual cost to the bank was less than two pounds.