This research aims to study and understand a complex social system through the development of an individual based hybrid model of the population of Leeds, UK. It attempts to demonstrate the importance of individual based modelling and simulation tools within the scope of demographic planning, as well as in application of a variety of substantive research and planning environments. The model adopts a hybrid modelling approach that combines the strength of two individual based modelling approaches: the first employs a dynamic spatial Micro-Simulation Model (MSM) and the second uses an Agent Based Model (ABM). This framework enables the modelling of a complex social system that is both theoretically and practically challenging. It attempts to provide a fuller picture of the population evolution through the simulation of discrete changes experienced by a large number of individuals within small areas and demonstrates heterogeneous characteristics in individuals and their behaviours reflecting not only individual demographic characteristics, but also interactions with each other and/or their local environment. This thesis describes the modelling method, system development, results alignment and model applications, as well as discussing the limitations and future potential of this model.