Data Quality & Verification

ESG Assurance Readiness

CSRD requires limited assurance of sustainability statements from FY 2024 onwards. The UK is moving towards mandatory assurance under UK SRS. ISSB-aligned reporting will follow. If your ESG data is not assurance-ready, you will discover this at the worst possible time — during the audit.

RSustain’s ESG Assurance Readiness service prepares your data, processes, and internal controls for third-party assurance — before the auditor arrives. Delivered entirely remotely, desk-based, using your existing documentation and data systems.

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Why Assurance Readiness Matters

ESG assurance is not a box-ticking exercise. Auditors applying ISAE 3000 (Revised) or ISAE 3410 expect the same rigour they apply to financial statements: documented methodologies, complete data trails, internal controls, management assertions, and evidence that supports every disclosed metric. Organisations that enter the assurance process unprepared face qualified opinions, delays, and reputational damage.

What Our Assurance Readiness Review Covers

Data Quality Assessment

Systematic review of your ESG data sources, collection processes, and calculations. Identification of data gaps, estimation methods, and areas where evidence is insufficient for assurance.

Internal Controls Review

Assessment of the controls governing ESG data collection, approval, and reporting. Mapping control gaps against ISAE 3000 requirements. Recommendations for control design and implementation.

Mock Assurance Engagement

A simulated limited assurance engagement following ISAE 3000/3410 procedures. Tests your team’s ability to respond to auditor queries, produce evidence, and explain methodologies under examination conditions.

Evidence Pack Preparation

Organisation of your supporting evidence into an audit-ready evidence pack: source documents, calculation workbooks, methodology statements, management assertions, and reconciliation schedules.

Assurance Standards We Prepare You For

  • ISAE 3000 (Revised) — International Standard on Assurance Engagements (non-financial information)
  • ISAE 3410 — Assurance Engagements on Greenhouse Gas Statements
  • AA1000 Assurance Standard (AA1000AS v3) — AccountAbility’s stakeholder-inclusive assurance framework
  • CSRD/ESRS — EU mandatory limited assurance requirement (moving to reasonable assurance)
  • UK SRS — FCA-mandated sustainability disclosures (assurance requirements expected)

Note: RSustain provides assurance readiness advisory — preparing your organisation for third-party assurance. Your statutory auditor or appointed assurance provider issues the formal opinion. RSustain’s group entity, Resilient Sustainance Private Limited (RSustain India), holds AA1000 Licensed Assurance Provider status for engagements where AA1000AS, ISAE 3000, and similar standards are the applicable framework.

Delivered Entirely Online

This service is delivered remotely through secure document review, video calls, and structured data exchange. No on-site visits required. Typical engagement: 4–8 weeks depending on the scope of disclosures and complexity of data systems.

Related Services & Resources

Frequently Asked Questions

What is ESG assurance?+

ESG assurance is an independent examination of an organisation’s sustainability disclosures by a qualified assurance provider. Limited assurance provides a “nothing has come to our attention” conclusion; reasonable assurance provides a positive “the information is fairly stated” conclusion. CSRD requires limited assurance, with a move to reasonable assurance expected.

Is ESG assurance mandatory in the UK?+

Not yet for UK-only reporters. However, UK companies in scope of CSRD (via EU subsidiaries) must obtain limited assurance. The FCA’s UK SRS framework is expected to introduce assurance requirements. Preparing now avoids a reactive scramble when requirements are confirmed.

Can this service be delivered remotely?+

Yes, entirely. All data review, controls assessment, mock assurance, and evidence pack preparation is conducted remotely through secure document exchange and video calls. No on-site visits are required.

Does RSustain issue assurance opinions?+

No. RSustain provides assurance readiness advisory — preparing your data, processes, and evidence for third-party assurance. The formal assurance opinion is issued by your statutory auditor or appointed assurance provider. RSustain’s group entity GSustain holds AA1000 Licensed Assurance Provider status for engagements where AA1000AS is the applicable standard.

Get Audit-Ready Before the Auditor Arrives

Book a free scoping call to assess your assurance readiness and plan your preparation programme.

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