Internal Audit Services

Internal audit services in UK help organisations assess and improve their risk management, governance, and internal control frameworks.

Effective internal audit provides independent assurance to boards and audit committees, supports compliance with the UK Corporate Governance Code for premium-listed companies, and aligns with UK legislation and sector rules such as the Companies Act 2006, Financial Conduct Authority (FCA) and Prudential Regulation Authority (PRA) handbooks for financial services, and other regulator guidance. A strong internal audit function also improves performance by highlighting control gaps, process inefficiencies, and emerging risks.

Common internal audit types include:

• Financial audits – accuracy of financial records, financial reporting controls, and fraud risk indicators.
• Operational audits – efficiency and effectiveness of end-to-end processes, cost, quality, and service objectives.
• Compliance audits – adherence to laws, regulations, licences, and industry frameworks applicable in the UK and specific sectors.
• IT and cybersecurity audits – technology governance, Information Technology (IT) general controls, application controls, data integrity, identity and access management, and cyber resilience.
• Environmental, Social and Governance (ESG) and sustainability audits - non-financial reporting controls, climate and sustainability disclosures, supply-chain risks, and data provenance.
• Third-party and supplier risk audits - onboarding, due diligence, contract and performance management, and monitoring.
• Programme assurance and change audits - major transformation, cloud migration, and systems implementation risks.

Many organisations typically adopt one of three models:

• In-house functions provide continuity, deep organisational knowledge and day-to-day proximity to management.
• Fully outsourced arrangements bring independence, sector expertise, access to specialist skills and the ability to flex resources in line with audit plans.
• Co-sourcing allows the Chief Audit Executive or Head of Internal Audit to retain accountability while supplementing the core team with external expertise or additional capacity.

Each model can be effective if designed to preserve the independence and objectivity required by the Institute of Internal Auditors (IIA) Standards. The choice often reflects the organisation’s scale, risk profile and resource needs. Co-sourcing, in particular, is increasingly common as it balances internal ownership with access to broader specialised skills. Whichever model is adopted, it should be clearly aligned to the IIA’s Three Lines Model, ensuring that internal audit provides robust, independent assurance across the full breadth of organisational risks.

An internal audit consultant helps organisations evaluate and strengthen their governance, risk management and control environments. This includes:

• Assessing risks and controls to test whether key processes, systems and safeguards are designed and operating effectively.
• Providing independent assurance by giving boards and audit committees confidence that risks are being managed appropriately.
• Advising on improvements by recommending pragmatic enhancements to controls, reporting and oversight, often informed by cross-industry insights and leading practice.
• Preparing for emerging challenges by supporting organisations in areas such as cyber, ESG, Artificial Intelligence (AI) and regulatory change, where specialist expertise is required.
• Building capability by transferring knowledge, developing frameworks and helping in-house teams adopt more efficient methods and technologies.

Engaging a consulting firm can help organisations:

• Access specialist expertise in areas such as cyber security, ESG, data analytics and regulatory change.
• Obtain independent assurance that is objective, benchmarked against leading practice and free from internal bias.
• Scale resources flexibly to match the size and complexity of the audit plan.
• Apply proven methodologies and tools that improve efficiency, coverage and insight.
• Stay aligned to UK regulatory expectations and evolving corporate governance standards.

Protiviti combines deep UK regulatory knowledge with global experience, delivering internal audit services that strengthen governance, risk management and compliance while helping organisations enhance performance. Our co-sourcing and outsourcing models give boards and audit committees confidence that risks are managed effectively, supported by practical recommendations that add value beyond compliance.

Digital transformation and AI are reshaping the way internal audit delivers assurance and advice. Key developments include:

• Automation of testing and evidence gathering, reducing manual effort and improving consistency.
• Enhanced data analytics, enabling 100% population testing, anomaly detection and thematic risk insights.
• Real-time and predictive monitoring, allowing auditors to move from retrospective reviews to continuous assurance and forward-looking risk assessment.
• Stronger fraud detection and control evaluation, leveraging machine learning to spot unusual patterns and emerging threats.
• Improved reporting and stakeholder engagement, with interactive dashboards and visualisation tools that make insights more accessible to boards and audit committees.

In the UK context, these capabilities align with heightened expectations under the evolving corporate governance regime, helping internal audit provide more timely, relevant and independent assurance while also advising management on technology-driven risks and opportunities.

Internal audit functions in the UK are evolving rapidly in response to regulatory change, technological disruption and stakeholder expectations. Current trends include:

• Governance and regulatory readiness – responding to the UK corporate governance reforms (including Provision 29), with greater emphasis on risk and control attestations.
• ESG assurance – providing independent reviews of sustainability reporting, climate risk and supply chain resilience.
• Cybersecurity and data privacy – expanding coverage of cyber threats, third-party risk and resilience testing.
• AI-driven audit analytics – using advanced analytics and automation to increase coverage, identify anomalies and deliver continuous assurance.
• Culture, conduct and ethics – evaluating softer controls, tone from the top and employee behaviours as drivers of risk.
• Agile and co-sourced delivery models – adopting flexible approaches and drawing on specialist consultants to keep pace with emerging risks.

Together, these trends reflect a shift in internal audit’s role: from primarily retrospective compliance testing to being a proactive, technology-enabled function that strengthens governance and supports long-term organisational resilience.

The frequency of audits depends on the organisation’s size, risk profile and regulatory environment. Most UK organisations operate to an annual internal audit plan, approved by the Audit Committee, that prioritises high-risk areas and provides balanced coverage over a multi-year cycle. Critical processes (such as financial reporting, cyber security or regulatory compliance) may be reviewed annually, while lower-risk areas may be audited less frequently. Increasingly, internal audit functions are also introducing continuous or real-time monitoring through data analytics, providing assurance on key controls in between formal audit reviews. The guiding principle is that audit frequency should be risk-based, dynamic, and aligned to the organisation’s governance obligations.

An EQA is an independent review of an internal audit function’s conformance with the IIA’s International Standards for the Professional Practice of Internal Auditing. The IIA requires that internal audit activities undergo an EQA at least once every five years.

An EQA provides:

• Assurance to the Board and Audit Committee that the internal audit function operates with independence, quality and consistency.
• Benchmarking against peers and leading practice, helping identify opportunities to enhance methodology, reporting and stakeholder engagement.
• Validation of credibility, strengthening the reliance regulators, investors and other stakeholders can place on the function’s work.

An EQA is both a regulatory requirement under professional standards and a valuable tool to drive continuous improvement and maintain stakeholder confidence.