4.13 The Green Book is the central Government framework for appraisal and evaluation, used across Government in the consideration and appraisal of policies, programmes and project.
4.14 The Treasury has published supplementary guidance to the Green Book on infrastructure, which will build on existing practices and support a consistent approach to the consideration and appraisal of infrastructure projects across Government.
4.15 The guidance covers four key areas:
• option appraisal, setting out the types of options that should be considered in order to maximise the value of infrastructure spending overall, including maintenance and smarter use of existing assets, targeted action to tackle network stress points, the development of large scale transformational projects, and demand management;
• ensuring that the wider impacts of infrastructure, for example on issues such as regional development, are included in an appraisal;
• valuing the opportunities and risks of sharing infrastructure assets; and
• valuing the impacts that infrastructure failure can have on society, and where it is proportionate to do so including values for these wider costs and benefits including relevant risk mitigation costs.