11. The supplemental note has two parts. In Part 1 - which may stand alone - the Committee sets out expectations for the external auditor and related questions the audit committee may ask the external auditor. The Committee, in Part 2, elaborates upon the expectations for the external auditor and provides additional material, including examples of ways in which the external auditor may consider meeting the expectations. Part 2 is of most relevance to the external auditor, but audit committees may also find it useful, eg where they may benefit from further information to help understand and interpret the external auditor's response to the questions in Part 1.

12. The guidance is structured around five key themes relevant to the quality of auditing the ECL estimate. The table below summarises key themes for audit quality and key components of the ECL estimate. The Committee expects that the external auditor will consider these components, among others, throughout the different stages of the audit of the ECL estimate and related disclosures, as these components are where the accounting and audit may be particularly challenging.