Much of the Hadley Centre's scientific contribution to the IPCC AR4 report was based on the Hadley Centre Global Environmental Model vn1 (HadGEM1). A huge amount of analysis of this model has been completed, including various model intercomparisons, and some of this work will be described. The model gives an excellent platform for inclusion of Earth System science modules, such as interactive land surface, ecosystem, carbon cycle and chemistry models. Such added complexity will form an important part of the future HadGEM2 and HadGEM3 models, and these will be described together with some future modelling plans at the Hadley Centre.