Internal Audit Co-Sourcing Companies in Birmingham: Practical Selection Guide (2026)
AC
Acumon Chartered Accountants·8 min read
This practical guide provides an overview of internal audit co-sourcing services companies in Birmingham, covering their expertise, service areas, and the types of organisations they support. The article offers a selection of companies rather than ranking them, with the aim of giving readers a clearer view of the options available in this market. The companies range from larger organisations with broad audit and advisory capabilities to more focused specialists working in specific areas of assurance and risk. This overview helps readers understand who these companies are, what they offer, and which factors may matter when choosing an internal audit co-sourcing partner.
Acumon
Acumon provides internal audit co-sourcing services for organisations seeking additional assurance support, specialist expertise, and flexible internal audit resources. The firm works with businesses, charities, and other organisations that need independent reviews of governance arrangements, risk management processes, and internal controls.
Its internal audit approach is based on structured risk assessment and tailored review programmes designed around each organisation’s objectives, operational environment, and regulatory responsibilities. Acumon supports existing internal audit functions by providing additional capacity, specialist knowledge, and independent perspectives on areas requiring further examination.
The firm works with organisations across different sectors, including commercial businesses, not-for-profit entities, and regulated organisations. Internal audit co-sourcing engagements are structured to complement existing teams and provide practical insights into control effectiveness, operational risks, and governance processes.
Acumon supports organisations operating in Birmingham and across the UK with internal audit services that align with recognised professional practices and organisational requirements. Its work focuses on helping management teams and boards maintain effective oversight of risks, controls, and internal processes.
Internal audit co-sourcing can support organisations during periods of growth, organisational change, increased regulatory expectations, or when additional specialist resources are needed. Acumon combines audit experience with risk advisory knowledge to provide support alongside internal teams.
Audit Capabilities
Acumon provides internal audit co-sourcing services across a range of organisational structures and business environments.
These include:
Internal audit co-sourcing support alongside existing audit teams
Risk-based internal audit planning and reviews
Governance and internal control assessments
Operational process reviews and improvement recommendations
Compliance and risk management reviews
Independent assurance support for management and boards
Internal audit engagements are designed around the organisation’s objectives, risk profile, and existing assurance framework. Acumon works with internal stakeholders to provide practical audit findings and recommendations that support stronger governance arrangements.
Regulatory Licences and Registrations
Acumon operates as a professional audit and advisory firm supporting organisations with assurance, governance, and risk-related services.
These include:
UK audit registration
Professional audit and accounting qualifications
Experience supporting regulated organisations
Internal audit and assurance expertise
Risk management and governance knowledge
Compliance-focused advisory experience
These professional credentials and areas of expertise support Acumon’s ability to deliver structured internal audit assignments for organisations requiring independent assurance and additional audit capability.
Core Services
Acumon provides internal audit and assurance services that support organisations in reviewing controls, managing risks, and strengthening governance processes.
These include:
Internal audit co-sourcing services
Outsourced internal audit support
Risk assessment and audit planning
Internal control reviews
Governance and compliance reviews
Operational assurance assessments
Risk management support
Acumon works with organisations that need additional internal audit resources while maintaining their existing governance structures and management oversight.
Its internal audit co-sourcing services support businesses that are:
Expanding operations and reviewing internal controls
Preparing for regulatory or governance changes
Strengthening risk management frameworks
Improving internal assurance processes
Managing complex operational environments
By combining audit expertise with a practical understanding of business processes, Acumon helps organisations evaluate their control environment and identify areas for improvement.
Address: 1-2 Craven Road, Ealing, London, W5 2UA, UK
Bishop Fleming
Bishop Fleming provides internal audit and risk assurance services to organisations across the UK, including outsourced and co-sourced internal audit arrangements. The firm supports public and private sector organisations with reviews covering governance, controls, risk management and compliance.
Its internal audit teams work with organisations that need additional audit resources, specialist reviews or support with maintaining effective assurance frameworks.
Key Facts
Ideal for: Public and private sector organisations requiring assurance support
Kreston Reeves offers internal audit outsourcing and co-sourcing services for organisations reviewing their governance arrangements, risk processes, and control environments. The firm supports businesses, charities, and public sector organisations through planned audit programmes, specialist assignments, and advisory engagements. Its services include internal audit reviews, technology assessments, fraud-related evaluations, and audit committee support, helping organisations strengthen oversight, improve controls, and maintain effective assurance frameworks.
Core services: Co-sourced internal audit, governance reviews, control assessments
Specialization: Internal audit advisory and assurance
Industries: Corporate, not-for-profit and public sector
Location: UK-wide
Contact Information
Website: www.krestonreeves.com
Address: 2nd Floor, 168 Shoreditch High Street, London, E1 6RA
Phone: +44 (0)330 124 1399
Twitter: x.com/KrestonReeves
LinkedIn: www.linkedin.com/company/kreston-reeves
Grant Thornton
Grant Thornton provides internal audit co-sourcing, outsourcing and advisory services for organisations that need additional assurance expertise. Its teams support internal audit functions with risk-based reviews, governance assessments and specialist resources.
The firm works with organisations across multiple sectors, providing support for both ongoing audit programmes and specific assurance projects.
Key Facts
Ideal for: Organisations needing access to wider audit expertise
BDO provides internal audit co-sourcing services as part of its wider risk advisory offering, supporting organisations with assurance and governance requirements. The firm’s teams assist with internal controls testing, governance reviews, technology risk assessments, and assurance programmes. BDO works alongside existing audit departments where additional expertise or capacity is needed, helping organisations review risk areas, evaluate controls, and strengthen internal audit processes through structured support.
Key Facts
Ideal for: Organisations requiring specialist audit support
Specialization: Governance, technology and compliance reviews
Industries: Commercial, financial services and public sector
Location: UK-wide
Contact Information
Website: www.bdo.co.uk
Phone: 0121 352 6200
Address: Two Snowhill Birmingham, B4 6GA, United Kingdom
LinkedIn: www.linkedin.com/company/bdo-llp
Instagram: www.instagram.com/bdo_uk
Protiviti
Protiviti provides internal audit sourcing services, including co-sourcing and staff augmentation support for organisations that need additional internal audit resources. Its teams combine internal audit methodology with expertise across business processes, technology and operational risks.
The company supports organisations looking to expand internal audit capability without creating additional permanent headcount.
Core services: Internal audit co-sourcing, outsourcing, audit support
Specialization: Technology and operational risk
Industries: Financial services, commercial and regulated sectors
Location: UK operations
Contact Information
Website: www.protiviti.com
Phone: +44.12.1616. 4600
Address: Second Floor, AIR, 35 Homer Road, Solihull B91 3QJ, United Kingdom
LinkedIn: www.linkedin.com/company/protiviti
Facebook: www.facebook.com/protiviti
Twitter: x.com/protiviti
Instagram: www.instagram.com/protiviti
Forvis Mazars
Forvis Mazars provides internal audit and risk advisory services for organisations seeking independent assurance over governance structures, internal controls, and risk management processes. Its internal audit teams support organisations through planned reviews, advisory assignments, and enhancements to existing assurance functions. The company helps organisations assess control effectiveness, review operational risks, and improve governance arrangements through structured audit support tailored to their specific requirements and business environment.
Key Facts
Ideal for: Organisations reviewing governance and controls
Deloitte provides internal audit co-sourcing and advisory services for organisations requiring support with governance, risk management, and control frameworks. Its internal audit teams assist organisations with assurance programmes, audit transformation initiatives, and specialist reviews where additional expertise is required. The company works with organisations across different sectors, helping them assess internal controls, review risk processes, and strengthen their overall assurance approach through structured audit support.
Key Facts
Ideal for: Large organisations with complex assurance needs
Address: Four Brindleyplace Birmingham, B1 2HZ United Kingdom
LinkedIn: www.linkedin.com/company/deloitte
Facebook: www.facebook.com/deloitteuk
Twitter: x.com/deloitteuk
RSM
RSM provides internal audit services for organisations seeking support with risk management, internal controls, and governance arrangements. Its teams deliver outsourced and co-sourced internal audit solutions tailored to organisational needs, helping businesses review processes and strengthen assurance frameworks. The company works with businesses and public sector organisations that require additional audit capability, specialist expertise, or independent support to evaluate risks, improve controls, and maintain effective governance practices.
Key Facts
Ideal for: Growing organisations and established audit teams
Crowe provides internal audit and risk advisory services, supporting organisations with assurance reviews, governance assessments, and internal control evaluations. Its internal audit teams work with organisations that need additional expertise for specific reviews, ongoing assurance programmes, or improvements to existing audit functions. The company supports clients across different sectors by reviewing risk management processes, assessing control effectiveness, and providing independent insights that help strengthen governance and operational oversight.
Key Facts
Ideal for: Organisations needing risk and compliance support
This guide highlights a selection of internal audit co-sourcing services companies serving Birmingham and the wider UK market. Providers vary in their approach, from specialist internal audit support to broader risk advisory and governance services.
The right option depends on factors such as organisation size, sector requirements, existing internal audit resources and the level of specialist expertise needed. A practical comparison of service scope, experience and delivery model can help organisations identify a suitable co-sourcing partner.
AC
Written by the Acumon team
Acumon is an ICAEW-registered firm of chartered accountants and registered auditors
based in London, with offices in Pitstone, Aylesbury and Bournemouth. Need advice on
anything covered here? Talk to us.
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