This chapter looks at the use of a web-based planning support system (PSS) to support participation in the development of a neighbourhood plan in England, a new community-led approach to planning. We outline the development of the toolkit, the capabilities and functions of the system and how it dealt with baseline analysis, participatory mapping and some of the monitoring and evaluation functions. The aim of our work was to assist in overcoming one of the great challenges facing communities wishing to develop their own plans and the difficulties they face in mobilising technical and planning expertise; in particular to meet the legal requirement to produce the evidence base for the neighbourhood. We report on the development and deployment of the toolkit and then discuss the lessons and what we see as future improvements. Many of the challenges around user engagement still persist today as they did 20 years ago when we first started this type of work.