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Feedback Statement - ISA (UK) 620 Using the Work of an Auditor’s Expert and ISAE (UK) 3000 Assurance Engagements Other Than Audits or Review of Historical Financial Information
The FRC does not accept any liability to any party for any loss, damage or costs howsoever arising, whether directly or indirectly, whether in contract, tort or otherwise from any action or decision taken (or not taken) as a result of any person relying on or otherwise using this document or arising from any omission from it.
© The Financial Reporting Council Limited 2026
The Financial Reporting Council Limited is a company limited by guarantee. Registered in England number 2486368. Registered Office: 13th Floor, 1 Harbour Exchange Square, London, E14 9GE
1. Introduction
1The Financial Reporting Council (FRC) is committed to acting as a proportionate and principles-based regulator that balances the need to minimise the impact of regulatory requirements on business, while working to support the delivery of high-quality audit and assurance work to maintain investor and wider stakeholder confidence in audit and assurance.
2The FRC strongly supports the alignment of ISAs (UK) and ISAE (UK) 3000 with the equivalent international standards, as issued by the International Auditing and Assurance Standards Board (IAASB), unless there is an overriding public interest reason for taking a different approach.
3The IAASB has issued narrow scope revisions to ISA 620 Using the Work of an Auditor's Expert, and ISAE 3000 Assurance Engagements Other Than Audits or Review of Historical Financial Information. The revisions were to maintain interoperability with the International Code of Ethics for Professional Accountants, issued by the International Ethics Standards Board for Accountants ('the IESBA Code'), following changes relating to the use of an external expert.
4The IAASB revisions were approved by the Public Interest Oversights Board (PIOB) in December 2025 and have an effective date of 15 December 2026.
5In June 2026, the FRC issued a public consultation on proposed revisions to ISA (UK) 620 and ISAE (UK) 3000. The proposed revisions intended to maintain alignment with the international standards through adoption of the narrow scope amendments. Where necessary, to reflect UK ethical requirements, the international standards are supplemented with a limited number of 'UK plus' material.
6Feedback received during the consultation was very supportive of the proposed revisions. Minor amendments have been made to the final standards as to address comments received, as set out below. The resulting standards have been issued alongside this feedback statement.
2. Summary of feedback and FRC response
Overall summary
7The consultation closed on 10 July 2026 and received 11 responses, representing a range of stakeholders (see table 1):
| Respondent type | Number of responses received |
|---|---|
| Audit Firm | 6 |
| Other | 3 |
| Professional Body | 2 |
Question 1: Do you agree that ISA (UK) 620 and ISAE (UK) 3000 should be revised to adopt the narrow scope amendments to the underlying international standards? If not, please indicate why and explain what actions, if any, that you believe should be taken.
ISA (UK) 620 – Using the Work of an Auditor's Expert
Summary of feedback
8Respondents were supportive of the adoption of the proposed narrow scope amendments and maintaining alignment with international standards. They noted that alignment with international standards helps to maintain consistency and supports the public interest.
9One respondent, while supporting the inclusion of UK plus material to highlight the relevant UK ethical requirements, suggested that further clarification of the application of the IESBA Code in the UK would be helpful.
10Several respondents supported the explicit prohibition of the use of auditor's experts when the auditor concludes that the expert does not have the necessary competence or capabilities or, that threats to that expert's objectivity cannot be eliminated or reduced to an acceptable level.1 Respondents noted that this prohibition made explicit a consideration that had been previously implicit in the standard. However, some respondents noted that there may be inconsistencies in determining what constitutes an 'acceptable level' of threat.
11Respondents also suggested that the prohibition should be repositioned to directly follow the evaluation of the expert's competence, capabilities and objectivity.
12Respondents sought clarification on the requirement in paragraph 11 for the auditor to agree, in writing when appropriate, certain matters with the auditor's expert. Respondents also sought clarification in the related appendix to provide the process by which, under this agreement, the auditor's expert is expected to communicate any changes in information provided to the auditor for the purpose of assessing the expert's objectivity.
FRC response
13UK auditors and assurance practitioners are subject to ethical requirements from two sources: the FRC Ethical Standard and ethical pronouncements established by the practitioners' relevant professional body. The FRC Ethical Standard was developed with the intent that it should adhere to the principles of the IESBA Code, including the International Independence Standards and be no less stringent.
14The IESBA Code was revised in December 2024 to introduce explicit requirements for professional accountants and sustainability practitioners when using the work of external experts. These revisions did not impact the International Independence Standard.
15UK professional accountancy bodies adopt the IESBA Code and require its use by their members. Where appropriate and consistent with national laws and regulatory requirements, revisions by IESBA relating to the use of external experts, will be incorporated by the UK professional accountancy bodies in their ethical codes.
16The FRC has retained UK plus material in ISA (UK) 620 as to ensure the auditor considers the relevant UK ethical requirements. References to IESBA Code have been maintained from the international standard as to maintain alignment, consistency of terminology and support multi-jurisdictional engagements.
17Determining whether threats to an auditor's expert's objectivity have been reduced to an acceptable level is a matter of professional judgement, based on the facts and circumstances of the engagement and the nature of the threats identified.
18The FRC has concluded that no additional material is required in paragraph 11 or to the related appendix, as this paragraph forms part of the extant standard. The form and detail of any agreement between the auditor and the auditor's expert will depend on the circumstances of the engagement and the relevant ethical requirements, as explained in application material (ISA (UK) 620, paragraph A24). Accordingly, it is a matter for the auditor and the expert to determine the most appropriate form of communication.
19Respondents also provided minor redrafting suggestions, which have been incorporated into the revised standard, including the repositioning of paragraph 9A.
ISAE (UK) 3000 – Assurance Engagements Other Than Audits or Review of Historical Financial Information
20A number of respondents highlighted the need to update ISAE (UK) 3000 to reflect conforming and consequential amendments arising from other standards which are effective on or before 15 December 2026. The FRC has reflected these amendments into the final revision of ISAE (UK) 3000.
Question 2: Is the proposed effective date, 15 December 2026, which is consistent with the effective date of the IAASB's revised standards, appropriate? If not, please give reasons and indicate the effective date that you would consider appropriate.
Summary of feedback
21Respondents were generally supportive of the proposed effective date of 15 December 2026. They noted that alignment with the effective dates of the international standards helps avoid piecemeal updates and promotes consistency across jurisdictions.
22One respondent did not support the proposed effective date, stating that it did not provide sufficient time for firms to update methodology and train personnel appropriately.
FRC response
23Given the limited scope of revisions, and that revisions align with international amendments, which were extensively consulted on, the FRC considers the effective date of 15 December 2026 to be appropriate.
3. Impact assessment
24The revisions to ISA (UK) 620 and ISAE (UK) 3000 maintain support of the underlying international standards issued by the IAASB. As to support UK ethical requirements, the international revisions have been supplemented with a very limited number of UK pluses.
25The FRC recognises that practitioners will need to incorporate the revisions into their methodologies and training. There may also be a need to discuss the revisions with practitioner's or other stakeholders. However, because the revisions are narrow in scope and align with international revisions, it is not foreseen that considerable cost will be incurred.
4. Appendix: List of consultation respondents
List of respondents
- Association of Chartered Certified Accountants
- Azets Audit Services Limited
- Chartered Accountants Ireland
- Deloitte LLP
- Ernst & Young LLP
- Grant Thornton UK LLP
- International Corporate Governance Network
- KPMG LLP
- Minerva Analytics
- SME Alliance Limited
- PricewaterhouseCoopers LLP
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Footnotes
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ISA (UK) 620 (Revised September 2026), paragraph 9A ↩