There is widespread concern about the need to deliver increased housing supply in the UK in order to address problems of affordability. One problem in achieving this is the nature of the planning system. UK housebuilding proposals need to be approved by Local Planning Authorities. The system in the UK differs from that in other areas of Europe in the extent to which decisions on planning permission are largely discretionary. Concern exists over delays in the evaluation of proposals and the negotiation of required changes. In practice, several factors may account for the time a new housing proposal takes to secure planning permission. Some delay may be due to planning whilst other factors relate to the ways in which proposals are formulated and/or specific site characteristics. Currently, there is little firm detailed empirical evidence on the causes of delay. The paper presents the findings from an ESRC funded research project that collected data on the time taken to gain planning permission for selected recent major housing projects from a sample of local authorities in southern England. Key characteristics of those developments such as number of units, location, etc were included. The whole chain of events in securing planning permission was also covered, including re-submissions and appeals. Hedonic analysis of the data highlights the factors determining the time development proposals take in the planning process. These results have been triangulated with interviews with key actors in the planning and development process in order to explore possible ways forward. The paper concludes with a range of recommendations.