The Green Book: appraisal and evaluation in central government

HM Treasury guidance on how to appraise and evaluate policies, projects and programmes.


The Green Book (2022)


The Green Book is the government’s guidance on options appraisal and evaluation.

From 1 November 2023, Ministers of the Crown have a legal duty to have due regard to the environmental principles policy statement when making policy. Where the duty applies, it is relevant for appraisals and evaluations that are conducted in line with the Green Book. This duty will be reflected in the Green Book when the document is next updated. Further information can also be found in the guidance on Enabling a Natural Capital Approach. The Green Book also contains details of the other statutory duties with which appraisals must comply.

Useful resources

Green Book practitioners and reviewers may benefit from the wider collection of accompanying guidance and materials including training and templates and support materials.

Previous editions of the Green Book

The previous 2003 edition of Green Book guidance is now withdrawn. For purposes of academic study and public information it may be found on the National Archives website.

Updates to this page

Published 18 April 2013
Last updated 16 May 2024 + show all updates
  1. Removed ‘Agile digital and IT projects: clarification of business case guidance’. This is still visible on the Green Book and accompanying guidance webpage. Moved the Business Case Guidance to a separate website

  2. The Green Book webpage is being updated to reflect the environmental principles policy statement coming into effect from 1 November.

  3. New link to collection page ( to improve signposting. Removed link to sign up to the Green Book newsletter. Link can be found on the collection page (Green Book and Accompanying Guidance and Documents).

  4. Updated for 2022

  5. Updated with HTML version of The Green Book 2020.

  6. Updated with The Green Book 2020.

  7. Reduced content on page.

  8. Updated with 'Infrastructure Business Case: International Guidance, Infrastructure Business Case: International Guidance Annexes and Infrastructure Business Case: International Case Study'.

  9. Added Business Case Templates documents to the page

  10. Updated with revised version of 'Access to training and accreditation in best practice business cases'.

  11. Replaced 'Public sector business cases using five case model: guidance' with 'Business case guidance for programmes', 'Business case guidance for projects', 'Business case guidance for programmes (International version)' and 'Business case guidance for projects (International version)'.

  12. New version of the Green Book published, as well as accompanying academic paper.

  13. Link to new guidance on Treasury approvals for programmes and projects added.

  14. Updated better business cases guidance published

  15. updated 'Access to training and accreditation in best practice business cases' publication

  16. Public sector business cases using the five case model: templates file (.doc) replaced (with (.odt)

  17. 'Agile digital and IT projects: clarification of business case guidance' published

  18. Updated guidance on public sector business cases using the 'five case model' published

  19. First published.

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