The Green Book
The HM Treasury Green Book is the UK Government’s official guidance on how to appraise policies, programmes, and projects. It provides a comprehensive framework for assessing value for money, supporting evidence based decision making across public sector investment.
Widely used across infrastructure, construction, and major capital programmes, the Green Book sets out best practice for evaluating options, assessing costs and benefits, and managing uncertainty and risk. It promotes a structured approach to business case development, ensuring that decisions are aligned with strategic objectives and deliver long term value.
The guidance spans the full lifecycle of a project, from early strategic outline cases through to full business case approval and post project evaluation. It places strong emphasis on transparency, consistency, and the use of robust data in decision making.
In an era of increasing scrutiny on public spending, sustainability, and long term outcomes, the Green Book plays a critical role in shaping how projects are defined, assessed, and delivered across the UK.
Key Highlights
UK Government standard for project appraisal and business cases
Focus on value for money and long term outcomes
Covers strategic, economic, commercial, financial, and management cases
Supports infrastructure and construction investment decisions
Emphasises risk, uncertainty, and option appraisal
Encourages evidence based and data driven decision making
The Green Book aligns strongly with Sterling’s capability to support robust, data driven cost and carbon estimating across the full project lifecycle.
Sterling enables organisations to produce more accurate and transparent inputs into business cases, supporting better decision making in line with Green Book principles.
Key areas of alignment include:
Early stage cost planning, supporting option appraisal and feasibility studies
Structured and auditable data, improving confidence in cost estimates and assumptions
Scenario modelling, enabling comparison of different design and procurement options
Lifecycle cost and carbon estimating, aligning with whole life value assessments
Integration of cost and carbon, supporting sustainability driven decision making
Ongoing forecasting and tracking, ensuring alignment between initial appraisal and delivery
By combining Green Book principles with Sterling’s SaaS platform, organisations can move from high level assumptions to detailed, evidence based estimating that supports stronger business cases and better investment outcomes.
Access the full Green Book guidance via HM Treasury:
https://www.gov.uk/government/publications/the-green-book-appraisal-and-evaluation-in-central-government
