This paper describes the results of a study into development processes and supporting tools appropriate for the development of safety critical and other high integrity using Ada. It describes an idealised development process and defines a minimum expected process as a subset of this. It then considers which activities in this process can be supported by tools and highlights activities which are not yet supported by commercial-off-the-shelf tools. An innovative approach to hazard analysis of the development process is also presented, with a suggested structure for a process safety case. Finally, the issues of process and tool assessment and the construction of better toolsets are addressed.