The paper describes geomorphological analysis and morphodynamic modelling of the double spit enclosed Exe Estuary, UK. The long-term morphodynamic behaviour of the Exe Estuary system and the surrounding shoreline is studied. The geomorphological analysis was based on available historic data on the estuary. The morphodynamic modelling methodology is two-fold: A systems model based on a Boolean approach is used to predict and investigate future morphodynamic response of the estuary to changes in external forcing. A 1-line shoreline model is used to investigate morphodynamics of Dawlish Warren spit (the only active spit at the mouth of the estuary) and its future morphologies. It was found that over long term time scales, the estuary will reach a stable morphological state or evolve cyclically between two morphological states, depending on future changes to environmental forcing such as waves and tides. It was also found that littoral transport control has a significant effect on the long term sustainability of the Dawlish Warren sand spit and the estuary as a whole