A portable electronic device includes an interface unit for connection to a removable storage medium; at least one data item store; a group of application handling units, at least one application handling unit in the group of application handling units providing an application handling user data; at least one access control module; and an access setup unit configured to receive a user identity from the removable storage medium via the interface unit, locate a user access control module associated with the received user identity, and force user data handling applications that view, read, or write data items to access data item stores in the portable electronic device via the user access control module. The user access control module restricts viewing, reading, and writing of data items to data areas provided for the user identity in data item stores in the portable electronic device.