Financial Audit Services

National Energy System Operator (NESO) makes sure that Great Britain has the essential energy it needs by ensuring supply meets demand every second of every day. The UK's 2023 Energy Act established an independent system planner and operator to help accelerate Great Britain's energy transition; creating NESO.

NESO is built on our previous experience as the National Grid Electricity System Operator (ESO), where we had extensive expertise in balancing electricity supply and demand 24/7, whilst making sure the networks we operated and the markets we served were prepared for the future. NESO was sold by National Grid to the UK Government on 1st October 2024 , becoming a public sector organisation from this date.

We require comprehensive financial audit services compliant with International Standards of Supreme Audit Institutions (ISSAI). The objective is to ensure NESO's financial, performance, and regulatory operations are conducted with transparency, accountability, and efficiency.

This specification provides the framework for the required audit services, including scope, planning, reporting, accountability, and SLAs. Scope of Services The audit firm will be responsible for delivering the following detailed services: Financial Audit o Provide reasonable assurance over NESO's financial records in accordance with applicable accounting standards (IFRS ). o Verify that financial statements are free from material misstatements due to fraud, error, or irregularities. o Evaluate internal financial controls, focusing on risks associated with financial misreporting, operational inefficiencies, or compliance failures. o Provide an audit opinion on the true and fair representation of NESO's financial position, performance, and cash flow. o Conduct testing of key accounts to provide reasonable assurance over the financial assertions. o Update NESO leadership and Audit & Risk Committee (ARC) regarding relevant changes in legislation and regulation. o Report on external audit progress to NESO leadership, including attendance at bi-monthly ARC meetings and other board or committee meetings as required. o Provide guidance to NESO leadership in particular the Chief Financial Officer (CFO), chair of ARC, director of financial control, and the accounting & reporting lead on accounting and financial matters. o Liaise and coordinate with the CFO, director of financial control and accounting & reporting lead via a monthly progress meeting to ensure full exchange of information. o Produce an annual SOC1 report evaluating the effectiveness of NESO financial controls in relation to transmission revenue charging, for external distribution to UK transmission owners, including National Grid Electricity Transmission (NGET).

NESO was sold by National Grid to the UK Government on 1st October 2024 , becoming a public sector organisation from this date. We require comprehensive financial audit services compliant with International Standards of Supreme Audit Institutions (ISSAI).

The objective is to ensure NESO's financial, performance, and regulatory operations are conducted with transparency, accountability, and efficiency. This specification provides the framework for the required audit services, including scope, planning, reporting, accountability, and SLAs. ________________________________________ 4. Scope of Services (Detailed) The audit firm is responsible for delivering the following detailed services: Financial Audit o Provide reasonable assurance over NESO's financial records in accordance with applicable accounting standards (IFRS ). o Verify that financial statements are free from material misstatements due to fraud, error, or irregularities. o Evaluate internal financial controls, focusing on risks associated with financial misreporting, operational inefficiencies, or compliance failures. o Provide an audit opinion on the true and fair representation of NESO's financial position, performance, and cash flow. o Conduct testing of key accounts to provide reasonable assurance over the financial assertions. o Update NESO leadership and Audit & Risk Committee (ARC) regarding relevant changes in legislation and regulation. o Report on external audit progress to NESO leadership, including attendance at bi-monthly ARC meetings and other board or committee meetings as required. o Provide guidance to NESO leadership in particular the Chief Financial Officer (CFO), chair of ARC, director of financial control, and the accounting & reporting lead on accounting and financial matters. o Liaise and coordinate with the CFO, director of financial control and accounting & reporting lead via a monthly progress meeting to ensure full exchange of information. o Produce an annual SOC1 report evaluating the effectiveness of NESO financial controls in relation to transmission revenue charging, for external distribution to UK transmission owners, including National Grid Electricity Transmission (NGET).