This paper describes an experimental corporate modelling system currently being developed jointly by the IBM (UK) Scientific Centre and Clwyd County Council. Although the system uses data for Clwyd County Council in determining the relationships within the model, the underlying structure of the system is a "general" one so that it may be easily adapted to suit the requirements of other local authorities. Clwyd County Council is one of the 47 non-metropolitan authorities in England and Wales. It is situated in North Wales with a population of around 360,000. The major industries are steel, chemicals, textiles, aircraft and farming. The revenue expenditure of the county for 1975/1976 as estimated in late 1975 was to be about £70 million and the captial expenditure around £11.0 million. In order to set the model in its proper perspective the current organisational structure and responsibilities of the reorganised (1 April 1974) local authorities in England and Wales are first reviewed. The nature of Corporate Planning, associated problems are discussed and an overall framework of a planning cycle is evolved. The structure of the modelling system which consists of a series of interlinking modules is described in detail and its potential role within the framework of the corporate planning cycle assessed. The paper concludes with a description of enhancements to the system currently in progress. © 1977.