The role of town planning (development control in particular) in urban design issues relating to new development is poorly understood and undervalued. The aim of this study was to investigate to what extent the planning process made a difference to outcomes, and what factors relating process and use of policy were more likely to lead to positive outcomes. Views of key players in the statutory planning decision-making process, in four case-study towns, were obtained through semi-structured interviews. The case-study towns included Ludlow, Dorchester, Chichester and Durham. An example of a 'successful' and an 'unsuccessful' major new development was examined for each town. The findings indicate that planning can play a significant role in securing a successful outcome, but organizational and political issues, as well as varying skill levels, can hinder the role and give rise to negative perceptions. It is clear that many factors have to work together to help ensure good outcomes, and there is no quick fix. Opportunities for improvement in the design input by planning, including local development frameworks, are considered.