Internal auditing plays an important role in helping UK businesses manage financial risks, improve operational efficiency, and maintain effective internal controls. As organisations grow, their financial transactions, employee responsibilities, and regulatory obligations become more complex. Without proper monitoring, businesses may face financial errors, fraud risks, compliance issues, and operational inefficiencies.
This is where internal auditors provide valuable support. They independently examine business processes, assess financial and operational controls, identify potential risks, and recommend improvements to strengthen an organisation’s overall performance.
However, one common question among UK business owners is: What do internal auditors actually do, and how much does hiring one cost?
Understanding their responsibilities, the auditing process, and typical UK fees can help businesses decide whether they need internal audit services and how to budget for them.
1. What Does an Internal Auditor Do?
An internal auditor evaluates how effectively a business manages its financial activities, operational processes, risk management procedures, and internal controls.
Unlike an external auditor, whose statutory audit responsibilities are governed by UK company law and applicable auditing standards, an internal auditor primarily works to help management and those charged with governance understand and improve the organisation’s systems.
Their responsibilities may include:
- Reviewing financial records and accounting procedures.
- Evaluating internal controls and approval processes.
- Identifying financial and operational risks.
- Assessing fraud prevention and detection procedures.
- Checking compliance with relevant laws and regulations.
- Reviewing procurement, payroll, and expense management.
- Evaluating IT systems and data security controls.
- Recommending improvements to business processes.
- Preparing internal audit reports for management.
The exact scope depends on the organisation’s size, industry, risk exposure, and internal audit requirements.
2. Key Responsibilities of Internal Auditors in UK Businesses
Internal auditors perform several activities to help organisations maintain accountability and reduce business risks.
Financial Controls and Reporting
They examine financial processes to determine whether transactions are recorded accurately and authorised appropriately. This may include reviewing payment approvals, bank reconciliations, expense claims, payroll records, and financial reporting procedures.
Risk Assessment and Management
Internal auditors identify risks that could affect business operations, financial stability, or regulatory compliance. They assess whether existing controls are sufficient and recommend measures to address weaknesses.
Fraud Prevention and Detection
They review processes that could expose businesses to fraud, including supplier payments, employee expenses, procurement, and access to financial systems. Internal auditors assess fraud controls but do not guarantee that every instance of fraud will be detected.
Regulatory Compliance
UK businesses operate under various legal and regulatory requirements. Depending on the industry, internal auditors may review procedures relating to financial reporting, data protection, anti-money laundering, employment practices, and other compliance obligations.
Operational Efficiency
Internal auditors examine how different departments operate and identify unnecessary costs, duplicated activities, inefficient approval procedures, and weaknesses in resource management.
IT and Cybersecurity Controls
As businesses increasingly rely on digital systems, internal auditors may review user access permissions, data protection arrangements, backup procedures, system changes, and cybersecurity controls.
3. How Does the Internal Audit Process Work?
The internal audit process generally follows a structured approach to ensure that business activities, financial records, and internal controls are examined systematically.
Most internal audits involve the following stages:
Step 1: Planning and Understanding the Business
The auditor learns about the organisation’s operations, business objectives, financial processes, and existing control systems. They identify areas that require attention and establish the audit scope.
Step 2: Risk Assessment
The auditor evaluates potential risks, including financial mismanagement, fraud, regulatory non-compliance, operational inefficiencies, and weaknesses in IT systems.
Step 3: Reviewing Documents and Records
Relevant financial statements, invoices, contracts, payroll records, transaction histories, policies, and supporting documents are examined.
Step 4: Testing Internal Controls
The auditor tests selected transactions and business procedures to determine whether existing controls are properly designed and operating effectively.
Step 5: Reporting Findings
After completing the review, the auditor prepares a report highlighting identified weaknesses, potential risks, and recommended improvements.
Step 6: Follow-Up and Monitoring
The auditor may conduct follow-up reviews to determine whether management has implemented the recommended corrective actions.
4. How Much Do Internal Auditors Charge in the UK?
The cost of hiring an internal auditor in the UK depends on several factors, including the organisation’s size, industry, audit scope, number of locations, and complexity of financial and operational processes.
There is no single standard fee for internal audit services. Some firms charge an hourly rate, while others offer fixed-fee engagements, daily rates, or annual internal audit contracts.
The following are useful indicative pricing considerations for UK businesses.
Internal Audit Cost Estimates
| Pricing structure | Indicative cost |
| Junior or public-sector internal audit contractor | £150–£400 per day |
| Senior internal audit contractor | £250–£500 per day |
| Internal audit manager | £350–£650 per day |
| Senior internal audit specialist | £450–£800 per day |
| Outsourced internal audit engagement | Depends on scope and agreed deliverables |
These are indicative contractor and market benchmarks, not guaranteed prices charged by outsourced accounting firms. Barclay Simpson’s 2026 salary guide, for example, reports that the most commonly quoted internal audit contractor day rate was £500–£599.
Barclay Simpson+1
For outsourced internal audit services, businesses should request a proposal based on the specific work required, rather than relying solely on contractor day rates.
What Factors Affect Internal Audit Fees?
Several factors can influence how much an internal audit firm charges.
Business Size and Complexity: Larger organisations usually have more transactions, employees, departments, and reporting requirements. This increases the time and resources required to complete an audit.
Audit Scope: A limited review of financial controls will generally require less work than a comprehensive assessment covering finance, procurement, payroll, IT security, and regulatory compliance.
Industry Requirements: Businesses operating in financial services, healthcare, insurance, and other regulated sectors may require specialist auditors with relevant industry knowledge.
Number of Locations: Organisations operating across multiple offices, branches, or countries may require additional testing, coordination, and site visits.
Auditor Experience: Experienced auditors and specialist professionals may charge higher fees because of their technical knowledge and ability to assess complex business risks.
Frequency of Audits: Businesses requiring monthly, quarterly, or annual internal audits should discuss ongoing arrangements with their provider. Regular engagements may offer more predictable budgeting.
5. Should You Hire an In-House or Outsourced Internal Auditor?
UK businesses generally have two main options when arranging internal audit services: employing an in-house auditor or outsourcing the function to an external specialist.
In-House Internal Auditor
An in-house auditor works directly for the organisation and regularly reviews its internal processes, financial controls, and operational risks.
This arrangement may suit larger organisations with complex operations, multiple departments, or ongoing internal audit requirements.
However, employing an internal auditor involves additional costs, including salary, recruitment, training, employee benefits, and professional development.
Outsourced Internal Auditor
An outsourced internal auditor is provided by an independent accounting or audit firm. Businesses engage the provider for specific assignments or ongoing audit support.
This arrangement can be particularly useful for small and medium-sized businesses that need professional audit services without maintaining a full-time internal audit department.
Benefits include:
- Access to experienced audit professionals.
- Flexible engagement arrangements.
- Reduced recruitment and employment costs.
- Access to specialist industry knowledge.
- Independent assessment of business controls.
- Support for periodic risk assessments and audit reviews.
The best option depends on your organisation’s size, budget, risk exposure, and ongoing audit requirements.
6. Is Internal Auditing a Legal Requirement for UK Businesses?
Not every UK business is legally required to maintain an internal audit function. The requirement depends on the organisation’s legal structure, industry, regulatory obligations, and applicable governance arrangements.
For example, certain regulated financial services businesses may have specific internal audit and governance requirements. Other organisations may introduce internal audits voluntarily to strengthen financial controls and risk management.
It is also important to distinguish internal auditing from a statutory external audit.
Under UK company law, qualifying small private limited companies may be exempt from statutory external audits if they meet the applicable conditions.
For financial years beginning on or after 6 April 2025, a company generally needs to meet at least two of these three criteria to qualify for the small-company audit exemption:
- Annual turnover of no more than £15 million.
- Balance sheet total of no more than £7.5 million.
- An average of 50 or fewer employees.
Certain exceptions apply, including situations where shareholders require an audit or specific legal requirements apply.
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Importantly, being exempt from a statutory audit does not mean a business cannot benefit from internal auditing. Internal audits can help identify weaknesses and improve financial and operational controls even when an external audit is not compulsory.
7. How to Choose the Right Internal Audit Firm in the UK
Selecting an appropriate internal audit provider is important because the quality of the audit can influence how effectively your organisation identifies and manages risks.
Consider the following factors before hiring an internal audit firm.
Professional Qualifications: Check whether the auditors hold relevant professional qualifications, such as CIA, ACA, ACCA, or other recognised credentials appropriate to the engagement.
Industry Experience: Look for a firm that understands your sector and the risks associated with your business operations.
Scope of Services: Confirm whether the provider can review financial controls, operational processes, IT systems, compliance procedures, and risk management arrangements as required.
Independence and Objectivity: Internal auditors should be able to assess business processes objectively without reviewing activities for which they are directly responsible.
Reporting and Communication: Choose a provider that delivers clear reports, explains identified weaknesses, and provides practical recommendations.
Transparent Pricing: Request a detailed quotation explaining the audit scope, estimated working days, professional fees, additional expenses, and reporting arrangements.
You should also ask for examples of previous engagements and client references where available.
8. When Should a UK Business Consider Hiring an Internal Auditor?
Internal auditing can be valuable at different stages of business development. It is particularly worth considering when an organisation experiences significant operational changes or increased financial complexity.
You may benefit from internal audit services if:
- Your business is expanding into new locations or markets.
- Financial transactions are increasing significantly.
- You have concerns about fraud or financial irregularities.
- Your organisation has complex approval and payment procedures.
- You need to strengthen internal controls.
- You operate in a regulated industry.
- You are preparing for investment, acquisition, or business restructuring.
- Management needs an independent assessment of operational risks.
An early review can help identify weaknesses before they develop into more expensive financial or operational problems.
Frequently Asked Questions (FAQs)
1. How much does an internal audit cost for a small business in the UK?
There is no fixed fee for small business internal audits. Costs depend on the number of processes reviewed, transaction volume, audit duration, and the experience of the auditor. A limited review may require considerably fewer resources than a comprehensive internal audit programme. Request a tailored quotation based on your requirements.
2. How often should a business conduct an internal audit?
The frequency depends on business size, industry, risk exposure, and regulatory requirements. Some organisations conduct quarterly reviews, while others follow an annual risk-based audit plan. High-risk areas may require more frequent monitoring.
3. What is the difference between an internal auditor and an external auditor?
An internal auditor evaluates an organisation’s risk management, internal controls, governance, and operational processes to identify improvements. An external auditor independently examines financial statements and provides an audit opinion where a statutory or other external audit is required.
4. Can a small business outsource internal audit services?
Yes. Small businesses can outsource internal audit services to independent accounting and audit firms. This provides access to professional expertise without the cost of employing a full-time internal auditor.
5. Does an internal auditor investigate fraud?
Internal auditors can assess fraud risks, review prevention controls, identify suspicious transactions, and examine weaknesses in financial procedures. However, a dedicated forensic investigation may require specialist professionals and a separate engagement.
6. What qualifications should an internal auditor have?
Relevant qualifications may include Certified Internal Auditor (CIA), ACA, ACCA, and other recognised accounting or audit credentials. The appropriate qualification depends on the nature of the audit, industry requirements, and the auditor’s responsibilities.
Conclusion
Internal auditors help UK businesses strengthen financial controls, manage operational risks, improve compliance, and maintain effective governance procedures. Their work goes beyond reviewing financial transactions, providing management with an independent assessment of how well the organisation operates.
The cost of internal audit services varies depending on business complexity, audit scope, professional experience, and engagement frequency. While larger organisations may benefit from a dedicated in-house audit team, outsourcing can be a practical and cost-effective option for small and medium-sized businesses.
Before hiring an internal auditor, evaluate your organisation’s requirements, compare service providers, and request transparent quotations. Investing in appropriate internal audit services can help protect business assets, improve operational efficiency, and support sustainable growth.
