Verification · ISO 14064-3 · ISO 14065 · UKAS
GHG verification standards:
UK guide
Independent verification of greenhouse gas emissions is a legal duty for UK ETS installations and optional almost everywhere else.
ISO 14064-3 is the standard a verifier applies, ISO 14065 is the standard the verifier is accredited against, and UKAS is the body that does the accrediting.
The assurance standard most people still name for GHG statements, ISAE 3410, is being withdrawn from 15 December 2026.
The vocabulary
Verification, assurance, certification and accreditation
Four words get used as if they meant the same thing, and the difference decides who you can hire and what they can sign.
Read the provisions and qualifications
Verification is a check of a greenhouse gas statement, usually against ISO 14064-3:2019, the standard for the verification and validation of GHG statements.
Assurance is the auditing profession’s word for much the same act over a wider set of information, and its standards come from the IAASB.
Certification is different again: ISO defines it as written assurance by an independent body that a product, service or system meets specific requirements, and ISO itself does not perform it.
Accreditation is the check on the checker: formal recognition that a certification or verification body operates to international standards.
ISO says accreditation of a certification body is not compulsory, so “not accredited” is not “not allowed” — unless a scheme or contract says otherwise, as UK ETS does.
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Terminology
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Verification
Module 03 / 04
Assurance
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Certification
Tables and tools
| Word | What it means here | Standard |
|---|---|---|
| Verification | A third party checks a GHG statement about past emissions | ISO 14064-3:2019 |
| Assurance | A practitioner gives limited or reasonable assurance over reported information | ISSA 5000; ISAE 3410 until withdrawn |
| Certification | A body issues a certificate that a system or product meets requirements | For example ISO 14001, via ISO/IEC 17021-1 |
| Accreditation | A national body confirms the checker is competent | ISO 14065 for GHG verifiers; UKAS in the UK |
Route finder
Do you need independent GHG verification?
Pick the situation you are in, and the finder gives the requirement, who may do the work and the standard, each with the source that settles it.
Seven situations cover almost every question UK readers bring: a UK ETS installation, a SECR disclosure, a listed company under the FCA rules, a voluntary GHG statement, an SBTi submission, an ISO 14068 carbon neutrality claim, and a customer or lender asking for “verified” numbers.
Only the first is a statutory duty to verify.
The SBTi and ISO 14068 rows are scheme rules: they bind you only if you choose the scheme.
The last row is contractual, and the contract’s wording is what governs it.
Do these emissions need verifying?
Is it needed? Required. The verified emissions report for the previous calendar year goes to the regulator by 31 March.
Who does it? A verifier accredited by UKAS to ISO 14065 and the Verification Regulation, with an accreditation scope covering your regulated activity.
To what standard? The UK ETS verification rules set out in the scheme’s guidance; ISO 14065 governs the verifier, not you.
GOV.UK, UK ETS for installations: how to comply — Bible [255], [810]
A map of the rules, not advice on a particular engagement.
Nothing is stored or sent.
Two regimes
Mandatory for UK ETS, voluntary for SECR
Under the UK Emissions Trading Scheme the duty is stated without qualification in GOV.UK’s guidance for installations: “Your chosen verifier must be accredited by the United Kingdom Accreditation Service (UKAS) to ISO 14065 and the Verification Regulation.”
Read the provisions and qualifications
The same guidance adds that the scope of the verifier’s accreditation must cover the regulated activity being reported.
The timing comes from DESNZ’s participation guidance: a verified emissions report for the previous calendar year goes to the regulator by 31 March each year, and our UK ETS guide covers the surrender cycle that follows.
Under SECR the position is the opposite.
The Environmental Reporting Guidelines say there is no requirement in the legislation for emission and energy use data, or the narrative on energy efficiency action, to be independently assured, though the government recommends it as best practice.
The same guidance says the statutory auditor of the financial statements is not required to audit environmental information in the strategic or directors’ report.
No credential of any kind is legally required to prepare a SECR disclosure.
One caution: that 2019 guidance names ISAE 3410 as a widely used standard, and ISAE 3410 is being withdrawn, so cite the guidance for the absence of a duty and not for which standard to use.
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UK ETS verification
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Accreditation scope
Module 03 / 04
Annual timing
Module 04 / 04
SECR distinction
Tables and tools
UK ETS verification is real and mandatory, but it verifies a regulated emissions report under one trading scheme.
It is not evidence that assurance of a company’s wider sustainability disclosures is required anywhere else in UK law.
The standards
ISO 14064-1, ISO 14064-3 and ISO 14065
| Standard | Whose rulebook | What it covers | Status on ISO’s record |
|---|---|---|---|
| ISO 14064-1:2018 | The reporting organisation | Quantifying and reporting an organisation’s GHG emissions and removals; GHG programme neutral | Edition 2, December 2018; stage 90.92, to be revised, with ISO/WD 14064-1.2 under development |
| ISO 14064-3:2019 | The verifier | Verification and validation of GHG statements | Edition 2, April 2019; stage 90.93, confirmed |
| ISO 14065:2020 | The verification body, as accredited | Requirements for bodies validating and verifying environmental information; a sector application of ISO/IEC 17029:2019 | Edition 3, December 2020 |
The family separates producing a GHG statement from checking it, and adds a third standard for the bodies that do the checking.
ISO 14064-1 says the series is “GHG programme neutral”: if a programme such as UK ETS applies, its requirements are additional to the standard.
Two traps sit in the records.
ISO 14064-1:2018 is current but already flagged for revision, so “confirmed 2024” and “to be revised” are both true and both worth saying.
ISO 14064-3’s 2019 edition reversed its title to “verification and validation”, and ISO 14065:2020 widened its scope from GHG statements to environmental information, so a citation built on older titles or the 2013 edition describes a superseded document.
The inventory a verifier tests is usually built under the GHG Protocol Corporate Standard, which says it is designed to produce a verifiable inventory but does not provide a standard for how verification should be conducted.
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Produce and verify
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Programme requirements
Module 03 / 04
Two traps
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Revision status
Who may verify
UKAS accreditation to ISO 14065
UKAS is the UK’s national accreditation body, appointed under regulation 3 of the Accreditation Regulations 2009.
Read the provisions and qualifications
The DBT–UKAS Memorandum of Understanding lists sixteen accreditation activities in its Appendix 1, and describes ISO 14065 there as “the accreditation of greenhouse gas validation and verification bodies”.
The memorandum also says UKAS will not undertake accreditation outside those activities, and calls itself an operational document that is not legally binding: the regulations are the legal footing.
UKAS accredits bodies, never consultants and never individuals, and its directory has no consultancy category; our UKAS accreditation guide covers the full list.
To check a verifier, search the UKAS directory and read its schedule of accreditation, which states the standard and the activities covered.
UKAS CertCheck, launched in June 2022, is for a different job: checking that a management-system certificate, such as ISO 14001, is UKAS-accredited.
A firm can apply ISO 14064-3 competently without holding ISO 14065 accreditation.
That is fine for a voluntary statement; it is not enough for UK ETS, which names the accreditation.
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National body
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Activities
Module 03 / 04
Government position
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Accredited bodies
Assurance standards
ISAE 3410, ISSA 5000 and the UK position
The IAASB announced on 8 May 2025 that it had approved the withdrawal of ISAE 3410, Assurance Engagements on Greenhouse Gas Statements, and that the withdrawal takes effect from the effective date of ISSA 5000.
Read the provisions and qualifications
ISSA 5000 is effective for periods beginning on or after 15 December 2026, so that is the date ISAE 3410 goes, though the announcement does not print it.
ISSA 5000 says it deals with both reasonable and limited assurance engagements, and it does not decide which level anyone needs.
The FRC issued ISSA (UK) 5000 on 12 November 2025, with the same effective date and earlier application permitted; the FRC describes it as intended for voluntary use.
For the UK the picture is not tidy: the FRC’s assurance standards page still lists ISAE (UK) 3000 (July 2020) as current and lists no ISAE (UK) 3410 at all.
ISSA (UK) 5000 paragraph 11 says a practitioner performing an ISSA (UK) 5000 engagement is not required to apply ISAE (UK) 3000, which is narrower than a UK withdrawal of it.
Our guide to sustainability assurance covers ISSA (UK) 5000 in full.
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Withdrawal decision
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Effective date
Module 03 / 04
Two levels
Module 04 / 04
UK standard
Tables and tools
- Nov 2024ISSA 5000 published by the IAASB
12 November 2024.
- 8 May 2025IAASB announces ISAE 3410 withdrawal
Effective from ISSA 5000’s effective date.
- Nov 2025FRC issues ISSA (UK) 5000
12 November 2025, for voluntary use.
- 15 Dec 2026ISSA 5000 and ISSA (UK) 5000 effective
ISAE 3410 withdrawal takes effect.
How much assurance
Limited or reasonable: who asks for which
| Who is asking | What they ask for | Source |
|---|---|---|
| UK ETS regulator | Verification of the annual emissions report by a UKAS-accredited verifier | GOV.UK |
| SECR | Nothing; independent assurance recommended as best practice | 2019 guidance |
| FCA final rules (listed companies) | Nothing; if assurance is obtained, the provider, the disclosures assured and the standards used | PS26/19 ¶2.45 |
| Government contracts (PPN 006) | Footprint “conducted to a reasonable level of assurance”, but “no requirement to have your carbon footprint audited” | Technical Standard ¶18 |
| SBTi, V1.3.1 | No third-party verification of base-year or recent-year data | Transition Guide |
| SBTi, V2.0 (from 1 Feb 2027) | Category A: third-party limited assurance of base-year emissions, low-carbon electricity calculations and target-setting metrics | Transition Guide |
PPN 006 is the one most often misread: it asks for a footprint good enough to stand scrutiny, not an audit, and our carbon reduction plan guide covers the rest of the plan.
The SBTi’s V2.0 duty is new, and its detail is in an assurance manual the SBTi says is forthcoming; our page on SBTi Net-Zero Standard V2.0 sets out the dates.
Scope 3 is where verifiers spend the most time and find the most estimates, which is why the FCA’s one-year relief for Scope 3 matters to the assurance plan as well; see Scope 3 under UK SRS.
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Procurement
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SBTi scheme
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Scope 3 evidence
The wider picture
No general duty to assure sustainability disclosures
UK ETS’s duty is the exception, and the rest of UK law is consistent about it.
Read the provisions and qualifications
Under the Companies Act 2006, section 414CB imposes disclosure duties for the non-financial and sustainability information statement and no assurance, audit or verification duty.
Under the FCA’s final rules in PS26/19, listed companies in UKLR 6, 14, 15, 16 and 22 report against UK SRS on a comply-or-explain basis for periods beginning on or after 1 January 2027, with first reports in 2028.
Assurance is not required: where a company has obtained it, paragraph 2.45 asks it to name the provider, which disclosures were assured and which assurance standards were used.
That keeps the shape the FCA consulted on: in CP26/5 ¶7.5 it said it was not proposing to set mandatory requirements for the assurance of sustainability reporting at this time.
The FRC’s sustainability reporting FAQ, last updated on 26 February 2026, still says reporting against UK SRS is not currently mandatory; that was true when written and predates PS26/19.
A register of sustainability assurance providers has been planned, but no register is live, so no UK rule yet tells you which assurers you may use.
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UK ETS exception
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Companies Act
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FCA framework
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Optional assurance statement
Buying verification
Choosing GHG verification services: seven questions
| Ask | Why it matters |
|---|---|
| Which standard will you verify or assure against? | ISO 14064-3 for a GHG statement; ISSA 5000 from 15 December 2026 for sustainability assurance; ISAE 3410 only for periods before its withdrawal takes effect |
| Limited or reasonable assurance? | The level drives the work and the wording of the opinion; choose it from what the reader of the report needs |
| Are you accredited, and for what? | Read the UKAS schedule: the standard and the activities covered. UK ETS needs ISO 14065 for your regulated activity |
| Did you help prepare the inventory? | A provider checking numbers it built is checking its own work |
| What is in scope? | Scopes, sites, period and whether Scope 3 categories are included |
| What materiality threshold will you apply? | It decides which errors the opinion can miss |
| What will you need from us? | Activity data, emission factors, boundary decisions and an audit trail a verifier can follow |
Most of the cost of verification is the time spent tracing numbers back to evidence, so the cheapest preparation is an inventory a stranger could rebuild.
That is mostly a systems question: our guide to carbon reporting software looks at audit trails, and the GHG Protocol’s five principles — relevance, completeness, consistency, transparency and accuracy — are the questions a verifier tests against.
A carbon neutrality claim adds its own verification layer, set out on our PAS 2060 and ISO 14068 page.
We do not verify, assure or certify anything; this page sets out the rules, and you can book a free 15-minute call if your case does not fit the finder.
Test yourself
Verification myths: true or false?
Most mistakes in this area come from carrying one regime’s rule into another.
The UK ETS duty gets cited for SECR, a recommendation in guidance gets read as a requirement, and an ISO standard gets described as something ISO certifies.
Each answer names the provision that settles it.
GHG verification: true or false?
A SECR disclosure must be independently verified.
A UK ETS installation’s verifier must be UKAS-accredited to ISO 14065.
ISO issues certificates for ISO 14064 verification.
Under the FCA’s final rules, a listed company must obtain assurance of its UK SRS disclosures.
ISAE 3410 remains available for GHG assurance after ISSA 5000 takes effect.
A carbon reduction plan for a government contract must have an audited footprint.
The GHG Protocol Corporate Standard says how verification should be conducted.
0 of 7 answered.
Nothing you choose is stored or sent.
A reading and preparation sequence
ghg verification standards: from the question to the evidence
- Step 0101
Four different activities
Four words get used as if they meant the same thing, and the difference decides who you can hire and what they can sign.Read the detail. - Step 0202
Which duty applies
Under the UK Emissions Trading Scheme the duty is stated without qualification in GOV.UK’s guidance for installations: “Your chosen verifier must be accredited by the United Kingdom Accreditation Service (UKAS) to ISO 14065 and the Verification Regulation.”Read the detail. - Step 0303
ISO standards
The family separates producing a GHG statement from checking it, and adds a third standard for the bodies that do the checking.Read the detail. - Step 0404
Accreditation
UKAS is the UK’s national accreditation body, appointed under regulation 3 of the Accreditation Regulations 2009.Read the detail. - Step 0505
Assurance transition
The IAASB announced on 8 May 2025that it had approved the withdrawal of ISAE 3410, Assurance Engagements on Greenhouse Gas Statements, and that the withdrawal takes effect from the effective date of ISSA 5000.Read the detail. - Step 0606
Assurance levels
PPN 006 is the one most often misread: it asks for a footprint good enough to stand scrutiny, not an audit, and our carbon reduction planguide covers the rest of the plan.Read the detail. - Step 0707
Reporting obligations
UK ETS’s duty is the exception, and the rest of UK law is consistent about it.Read the detail.
Dates, with their status
The relevant dates, drawn in order
- 12 November 202401
ISSA 5000 published
The IAASB publishes the international sustainability assurance standard, covering limited and reasonable assurance. - 8 May 202502
ISAE 3410 withdrawal announced
The withdrawal is tied to ISSA 5000’s effective date. It does not establish a new legal duty for companies to obtain assurance. - 12 November 202503
UK standard issued
The FRC issues ISSA (UK) 5000. Its engagement requirements are separate from the law or scheme deciding whether assurance is needed. - 15 December 202604
Effective reporting periods and dates
ISSA (UK) 5000 applies to assurance engagements on information for periods beginning on or after this date, or as at a specific date on or after it. Earlier application is permitted.
Continue your research
Related reporting guides, one question at a time
Frequently asked
GHG verification, answered
Do I need my carbon footprint verified for my sustainability report in the UK?
Usually not by law.
SECR carries no requirement for independent assurance, the Companies Act strategic report duties carry none, and the FCA’s final rules for listed companies ask only that a company which has obtained assurance says so, naming the provider, the disclosures assured and the standards used.
The exceptions are UK ETS installations, which must have their annual emissions report verified, and contracts, lenders or schemes that ask for it.
Does UK ETS require accredited verification of emissions data?
Yes.
GOV.UK’s guidance for installations says the chosen verifier must be accredited by UKAS to ISO 14065 and the Verification Regulation, with an accreditation scope covering the regulated activity being reported.
The verified emissions report for the previous calendar year goes to the regulator by 31 March each year.
Does SECR require independent verification or assurance?
No. The government’s Environmental Reporting Guidelines say there is no requirement in the legislation for emission and energy use data, or the energy efficiency narrative, to be independently assured, though they recommend it as best practice.
The statutory auditor is not required to audit the environmental information either.
What is the difference between ISO 14064-1, ISO 14064-3 and ISO 14065?
ISO 14064-1 is the standard an organisation uses to quantify and report its own greenhouse gas inventory.
ISO 14064-3 is the standard a third party applies to verify or validate a GHG statement.
ISO 14065 sets requirements for the bodies that do the verifying, and it is what UKAS accredits them against.
What does UKAS validation and verification mean?
UKAS accredits validation and verification bodies: it checks that a body is competent and impartial to verify environmental information, measured against ISO 14065.
The DBT–UKAS memorandum lists ISO 14065 among UKAS’s appointed activities as the accreditation of greenhouse gas validation and verification bodies.
UKAS accredits bodies, never consultants or individuals.
Is ISAE 3410 still the standard for GHG statement assurance?
It is being withdrawn.
The IAASB announced on 8 May 2025 that the withdrawal of ISAE 3410 takes effect from the effective date of ISSA 5000, which is for periods beginning on or after 15 December 2026.
That date is derived from ISSA 5000; the announcement does not print it.
Is ISAE (UK) 3000 withdrawn for UK sustainability engagements?
Not as far as any primary source shows.
The FRC’s assurance standards page still lists ISAE (UK) 3000 (July 2020) and lists no ISAE (UK) 3410.
ISSA (UK) 5000 paragraph 11 says a practitioner performing an ISSA (UK) 5000 engagement is not required to apply ISAE (UK) 3000, which is narrower than a withdrawal.
What is the difference between limited and reasonable assurance?
They are two levels of assurance engagement, and ISSA 5000 deals with both.
Reasonable assurance is the higher level and costs more work; limited assurance is the lower level most voluntary GHG engagements use.
ISSA 5000 does not decide which level anyone needs: a contract, scheme or regulator does, and under SBTi V2.0 Category A companies need limited assurance.
Can a consultant verify our emissions?
Anyone can offer verification, but UKAS accredits verification bodies, not consultants or individuals, and UK ETS requires a UKAS-accredited verifier.
Check a provider’s accreditation and scope in the UKAS directory, and ask whether the same firm helped prepare the inventory it would be checking.
Will verification be required under UK SRS?
Not under the rules as made.
PS26/19 brings UK SRS reporting on a comply-or-explain basis for listed companies in UKLR 6, 14, 15, 16 and 22, for periods beginning on or after 1 January 2027, and assurance is not required; where it is obtained, the report names the provider, the disclosures assured and the standards used.
Sources
Primary sources
Every figure, date and status on this page traces to the instrument’s owner.
Secondary commentary is never the source for a number.
- GOV.UK (DESNZ)UK Emissions Trading Scheme for installations: how to comply
The verifier must be UKAS-accredited to ISO 14065 and the Verification Regulation.
- GOV.UK (DESNZ)Participating in the UK ETS
A verified emissions report by 31 March each year.
- Defra / BEISEnvironmental Reporting Guidelines including SECR guidance (March 2019)
No requirement in the legislation for SECR data to be independently assured.
- ISOISO 14064-1:2018 catalogue record
Organisation-level quantification; stage 90.92, to be revised.
- ISOISO 14064-3:2019 catalogue record
Verification and validation of GHG statements; confirmed.
- ISOISO 14065:2020 catalogue record
Requirements for bodies validating and verifying environmental information.
- ISOCertification
ISO does not perform certification; accreditation is not compulsory.
- legislation.gov.ukAccreditation Regulations 2009 (SI 2009/3155), regulation 3
The appointment of UKAS as the national accreditation body.
- DBT / UKASMemorandum of Understanding 2023, Appendix 1
ISO 14065: the accreditation of GHG validation and verification bodies.
- UKASFind an organisation and CertCheck
The directory of accredited bodies; CertCheck for management-system certificates.
- IAASBISSA 5000, General Requirements for Sustainability Assurance Engagements
Published 12 November 2024; effective for periods from 15 December 2026.
- IAASBIAASB announces withdrawal of ISAE 3410 (8 May 2025)
Withdrawal takes effect from ISSA 5000’s effective date.
- FRCISSA (UK) 5000 (12 November 2025)
¶15 effective date; ¶11 on ISAE (UK) 3000.
- FRCAssurance standards
Still lists ISAE (UK) 3000 (July 2020); no ISAE (UK) 3410.
- Financial Conduct AuthorityPS26/19: Aligning listed issuers’ sustainability disclosures with international standards
¶2.45: name the provider, scope and standards where assurance is obtained.
- Financial Conduct AuthorityCP26/5 (the consultation PS26/19 finalises)
¶7.5: no mandatory assurance requirement proposed.
- FRCSustainability reporting developments: FAQs (last updated 26 February 2026)
Predates PS26/19; cited for its date-stamped position.
- legislation.gov.ukCompanies Act 2006, section 414CB
Disclosure duties; no assurance duty.
- Cabinet OfficePPN 006 Technical Standard for Carbon Reduction Plans, ¶18
Reasonable level of assurance, but no requirement to have the footprint audited.
- SBTi ServicesGuide for Companies in the Transition to CNZS V2.0 (June 2026)
Category A limited assurance under V2.0; none required under V1.3.1.
- GHG ProtocolCorporate Accounting and Reporting Standard
Designed for a verifiable inventory, but sets no verification standard.