The Convective Storm Initiation Project (CSIP) aimed to further the understanding of the mechanisms responsible for the initiation of precipitating convection in the maritime environment of southern England; i.e. to understand why convective clouds form and develop into precipitating clouds in a particular location. The project was centred on the 3 GHz (CAMRa) and 1275 clear-air (ACROBAT) radars at Chilbolton and used a number of the new UK Universities' Facility for Atmospheric Measurement (UFAM) mobile instruments. The project consisted of a pilot field campaign in July 2004 and the main field campaign in June, July and August 2005.