This is general information about UK rules, checked on the date above. It is not legal advice, and rules change. For a decision that matters, check the sources below or ask a qualified adviser.
If a large customer has recently sent you a questionnaire about your carbon emissions, you are probably wondering whether you legally have to answer it. The honest answer is that for most UK businesses there is no direct legal duty to report Scope 3, but commercial pressure can be just as real.
The short version
- Scope 3 covers emissions across your value chain, split into 15 categories.1
- UK Sustainability Reporting Standards have been finalised, but are currently available for voluntary use.2
- Streamlined Energy and Carbon Reporting applies to quoted and large companies, and is voluntary for others.3
- Suppliers bidding for large central government contracts can face a specific requirement.4
What Scope 3 means
Greenhouse gas reporting usually splits emissions into three groups: your direct emissions (Scope 1), purchased energy (Scope 2) and everything else in your value chain (Scope 3).
The GHG Protocol’s Corporate Value Chain Standard lets companies assess their entire value chain emissions impact and identify where to focus reductions.5 Its guidance covers methods for each of the 15 categories of Scope 3 emissions, such as purchased goods and services, transportation and distribution, and use of sold products.1
What UK rules say today
UK Sustainability Reporting Standards. The UK government consulted on UK versions of the international standards IFRS S1 and IFRS S2, and has now published the finalised UK SRS S1 and S2. They are available for voluntary use by any entity that chooses to use them.2 The government and the Financial Conduct Authority will consider whether to introduce requirements for certain UK entities to report against them.2 So watch this space, particularly if you are a listed company, or sell to them.
Streamlined Energy and Carbon Reporting (SECR). This requires UK quoted companies, large unquoted companies and large limited liability partnerships to disclose their energy use and greenhouse gas emissions. The government encourages all other companies to report similarly, but this remains voluntary.3
Government contracts. Procurement Policy Note 006 applies to central government contracts valued above £5 million a year. Bidders must provide a Carbon Reduction Plan covering Scope 1 and 2, and a defined subset of Scope 3 emissions.4 The technical standard sets out which categories count: upstream transportation and distribution, waste generated in operations, business travel, employee commuting and downstream transportation and distribution.6
Why smaller firms get asked anyway
A larger customer’s Scope 3 includes the emissions of its suppliers, and those suppliers may be you. So a company that does have to report, or wants to, will often pass the question down its supply chain. You may not have a legal duty, but you could still have a commercial reason to answer.
This is our reading of how the pressure works in practice, and it varies a lot by sector. If a customer asks, the best first step is simply to find out what they need, in what format and by when.
A sensible first response
If you have received a request, here is our suggested approach:
- Do not panic, and do not make up numbers. Being open about uncertainty is far better than false precision.
- Ask what is actually needed. A customer may only need a few things, or may accept estimates this year.
- Start with what you know. Your energy bills, fuel and travel records are often enough for Scope 1 and 2.
- Screen Scope 3. Work out which categories are likely to be biggest for your business. For many, it is purchased goods and services.
- Use recognised methods. The UK government publishes annual conversion factors for company reporting, covering Scope 1, 2 and 3.7
- Record your sources and assumptions. You will need them next year, and someone may ask.
Be careful with green claims
Once you have figures, you may want to promote them. Be careful about how you do this. Any public claim should be accurate and backed by evidence, and we would recommend having it checked. A customer questionnaire and a marketing claim are very different things.
What to watch next
Things are moving, so check the current position before making decisions:
- Whether the FCA introduces reporting requirements for listed companies under UK SRS. The government’s page refers to an FCA consultation on the UK Listing Rules.2
- Whether the government extends requirements to other companies.
- Changes to procurement policy, which can flow down to suppliers.
Understanding the rules is the easy part. Getting numbers you can defend is harder, and our article on Scope 3 data quality explains why. If you would like help, our Scope 3 reporting service prepares the data and the method, while independent assurance has to come from a separate provider.
Sources
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GHG Protocol, Scope 3 Calculation Guidance, accessed 7 November 2026. ↩ ↩2
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Department for Business and Trade, UK Sustainability Reporting Standards, accessed 7 November 2026. ↩ ↩2 ↩3 ↩4
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UK Government, Environmental reporting guidelines, including Streamlined Energy and Carbon Reporting requirements, accessed 7 November 2026. ↩ ↩2
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Cabinet Office, PPN 006: taking account of Carbon Reduction Plans, accessed 7 November 2026. ↩ ↩2
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GHG Protocol, Corporate Value Chain (Scope 3) Standard, accessed 7 November 2026. ↩
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Cabinet Office, PPN 006: technical standard for completion of Carbon Reduction Plans, accessed 7 November 2026. ↩
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Department for Energy Security and Net Zero, UK government conversion factors for company reporting, accessed 7 November 2026. ↩
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