The Green Book
The Green Book 2026 is HM Treasury’s updated guidance on appraisal for proposals involving public spending.
The revised edition reinforces the framework for assessing social value, managing risk and ensuring value for money across policies, programmes and projects. It clarifies the appraisal process, from establishing the case for change and generating options, through to detailed cost-benefit analysis and identifying a preferred option, while maintaining alignment with the Five Case Model and the wider ROAMEF cycle.
The update strengthens emphasis on proportionality, distributional and place-based analysis, statutory duties and long-term impacts, supporting more robust, transparent and consistent investment decisions across government.