1. A method for analysing incoming data, comprising the steps of: a) processing the incoming data in segments to output a sequence of segment types by extracting one or more properties of an incoming data segment and forming an Unknown Property Vector for each segment of data in the incoming data; and b) processing the sequence of segment types to identify events in the incoming data; wherein the sequence of segment types is determined, for each segment, by reference to a set of Reference Property Vectors that are relevant to the Unknown Property Vector.