At least one topic in text data is determined by a topic determiner (4). A topic thread determiner (5) identifies in the text data context data associated with the at least one determined topic and provides topic representation data defining a graphical representation of the at least one topic in which are distributed visual indicia representing at least some of the context data with the distribution of the visual indicia indicating the positions within the text of the corresponding context data. The topic thread determiner (5) provides the topic representation data for display to a user on a display.