Graphical user interface and method for displaying hierarchically structured information

A graphical user interface (GUI) is described which enables hierarchically structured information to be presented and analysed by a user quickly and easily. In one example, the GUI is for a fraud management system and the information is about "alarms". Each alarm is an indicator of potential fraud and several types of alarm are presented, where the type of an alarm depends on the method of obtaining that alarm. The types of alarm are arranged in a hierarchical structure and a representation of the hierarchical structure is displayed on a display screen. A user is able to select one or more parts of the hierarchical structure in order to display information about all the alarms of the selected types and subtypes. This enables the user to quickly and easily view required information without the need to make many user actions and selections. The representation of the hierarchical structure may be tailored by the user. This is done by collapsing or expanding parts of the hierarchical representation.