Explain the provisions when a banker must refuse payment and when a banker may refuse payment under the Negotiable Instruments Act, 1881.

Under the Negotiable Instrument Act, 1881, in the following cases the authority of the banker to honour customer's cheque comes to an end, he must refuse to honour cheques issued by the customer: When a customer countermands payment i.e., where or when a customer, after issuing a cheque issues instructions not to honour it, the banker must not pay it. When the banker receives notice of customer's death. When customer has been adjudged an insolvent. When the banker receives notice of customer's insanity. When an order (e.g., Garnishee Order) of the Court, prohibits payment. When the customer has given notice of assignment of the credit balance of his account. When the holder's title is defective and the banker comes to know of it. When the customer has given notice for closing his account. In the following cases, the banker may refuse to pay a customer's cheque: When the cheque is post-dated. When the banker has no sufficient funds of the drawer with him and there is no communication between the bank and the customer to honour the cheque. When the cheque is of doubtful legality. When the cheque is not duly presented, e.g., it is presented after banking hours. When the cheque on the face of it is irregular, ambiguous or otherwise materially altered. When the cheque is presented at a branch where the customer has no account. When some persons have joint account and the cheque is not signed jointly by all or by the survivors of them. When the cheque has been allowed to become stale.