The relationship between a banker and customer depends on the type of activities and services provided by the bank. The Banking Regulation Act 1949 defines banking as accepting deposits from the public that are repayable on demand and allowing withdrawals by cheque. Customers can be existing customers with accounts, former customers, potential customers, or those who visit a branch but don't have accounts. The relationship is based on a contract and terms and conditions, and can take various forms like debtor-creditor for deposits, creditor-debtor for loans, trustee for safekeeping assets, bailee-bailor for safe deposit lockers, or lessor-lessee for rented property.