Guidance

The BSI Nature Investment Standards

Published 24 March 2026

The purpose of the Nature Investment Standards

Private sector action is necessary to meet UK government’s ambitious environmental commitments. Nature markets provide an effective way to mobilise this, enabling businesses to pay for the benefits and services that nature provides.

These benefits, such as clean air and water, carbon storage, biodiversity, and flood protection, can be traded as credits, providing farmers and land managers with an additional income stream. As set out in the voluntary carbon and nature markets consultation, government is committed to ensuring these markets develop with integrity.

The British Standards Institution (BSI), funded by Defra, and supported by the devolved governments, has developed a set of voluntary standards designed to guard against greenwashing and bring greater confidence and consistency to nature markets in the UK. 

The Nature Investment Standards (BSI Flex 700 series) set out clear principles for the supply, storage and trade of nature credits. There are 5 BSI standards in this set:

• Overarching Principles and Framework – Specification (BSI Flex 701)
• Supply of Biodiversity Benefits – Specification (BSI Flex 702)
• Supply of Nature-based Carbon Benefits – Specification (BSI Flex 703) [in development]
• Supply of Nutrient Benefits – Specification (BSI Flex 704)
• Community Engagement and Benefits – Code of Practice (BSI Flex 705) [in development]

The standards will ensure that investments deliver genuine environmental benefits and that market functions operate with transparency and fairness. They also promote actions to achieve co-benefits, including by encouraging greater participation by local communities in nature market projects. 

Where to find the Nature Investment Standards

The standards are hosted on the BSI website, where users can access the full documents free of charge: Nature Investment Programme.

Supporting tools and documents are available on the BSI’s Nature Investment Standards Hub (you will need to log in to the hub which is free of charge).

Who should use the Nature Investment Standards

The standards are voluntary, and intended for adoption by those involved in the supply, storage and trade of nature credits, including:

• credit suppliers (such as farmers, land managers and nature project developers)
• crediting programmes (such as codes and schemes)
• market intermediaries (such as registries and trading platforms)

Buyers and investors can also use the standards to identify suppliers of high integrity credits and processes to supply those credits.

The BSI Nature Investment Standards apply across the UK to ensure a consistent domestic investment landscape for nature.

How to conform with the Nature Investment Standards

The UK and devolved governments are committed to maintaining the highest levels of integrity in nature markets. Assurance is critical to this, building confidence by demonstrating claims of conformity to the standards are robust.

Government is developing a proportionate system of assurance, designed to balance rigour with accessibility, to support adoption of the standards. It will provide a means to demonstrate the integrity of credits and processes to supply them.

The assurance framework will be implemented in phases. It will accommodate the needs of users at different stages of development in this growing market.

This starts with a transition period of self-assessment, which will be a minimum of 2 years starting in March 2026. Following the transition period, the government plans for accredited conformity assessment bodies (CABs) to become the primary bodies responsible for assuring against the standards. This phased approach – starting with self-assessment – offers a low cost, accessible path to demonstrate progress and build readiness for independent assurance.

On 24 March, BSI published guidance to help users adopt the standards. This can be found on Nature Investment Standards Hub (you will need to log in to the hub which is free of charge): 

• BSI Nature Investment Standards Summary Self-Assessment Guidance: a brief overview of the guidance for performing self-assessment
• BSI Nature Investment Standards Assessment Guidance: more comprehensive guidance to support understanding of assurance and the assessment process, including useful tips and insights
• BSI Appendices: practical tools to help complete an assessment. Appendix A – Self-declaration template, Appendix B – Self-assessment template, Appendix C – Evidence lists

The UK and devolved governments will review this approach to assurance during the transition phase.