A transaction processing system for processing a transaction between a supplier and a customer, said system comprising a supplier device for initiating the transaction, a system server and a mobile communication device, said device containing a message processing program module for enabling local verification of the transaction within the mobile device, wherein a transaction message is sent from the supplier device to the system server, a message requesting payment for the transaction is sent from the system server to the mobile communication device, the transaction is authorized and verified at the mobile telecommunications device from which a verification message is sent back to the system server, and the transaction is then processed.