Cyber Security Audit Companies in the UK: A Practical Overview and Selection Guide

Cyber security has become a board-level priority for organisations of every size. As regulatory expectations evolve and cyber threats grow more sophisticated, businesses are placing greater emphasis on understanding how well their systems, controls and governance frameworks protect critical information.

The UK is home to a broad range of cyber security audit providers, from specialist security consultancies to multidisciplinary advisory firms that combine cyber expertise with audit, risk and regulatory services. While many organisations offer similar core capabilities, their experience, sector focus and approach to assurance can vary considerably.

This guide highlights a selection of companies providing cyber security audit services across the UK. Rather than ranking providers, it offers practical context to help organisations understand the different types of firms operating in the market, the services they typically provide, and the environments in which they are most experienced. Whether you’re strengthening your cyber resilience, preparing for regulatory scrutiny or seeking independent assurance over your security controls, understanding the available options is an important first step.

Acumon

Acumon is a UK firm of chartered accountants and advisors providing cyber security audit services to companies and organisations across the UK.

The firm works with organisations ranging from owner-managed businesses through to larger corporate groups, regulated entities and international organisations. Cyber security audit services are designed to help organisations assess cyber security risks, strengthen information security controls and support regulatory and governance requirements.

Acumon provides cyber security audit services across a range of technology and business environments, including cyber risk assessments, security control reviews, governance evaluations and technology assurance. Services are delivered using a structured methodology tailored to each organisation’s operational environment, regulatory obligations and cyber risk profile.

Acumon holds a Public Interest Entity (PIE) audit licence, enabling the firm to support organisations subject to enhanced regulatory oversight in the United Kingdom. In addition to its UK statutory audit registration, the firm also maintains audit licences in the Cayman Islands, British Virgin Islands (BVI), Jersey and Isle of Man, supporting organisations operating across international structures and reporting environments.

As organisations become increasingly dependent on digital systems, effective cyber security governance and resilient internal controls are essential. Acumon works with boards, finance teams and management to evaluate cyber security arrangements while supporting stronger governance, risk management and operational resilience.

Cyber Security Audit Capabilities

Acumon provides cyber security audit services across a wide range of organisational structures and sectors.

These include:

• UK limited companies and corporate groups
• regulated organisations
• international group structures
• technology-driven businesses
• charities and not-for-profit organisations
• businesses strengthening cyber security governance

Cyber security audit engagements are typically led by experienced professionals with direct involvement throughout the engagement.

Regulatory Licences and Registrations

Acumon holds several audit registrations that enable it to support organisations operating across multiple jurisdictions.

These include:

• UK statutory audit registration
• Public Interest Entity (PIE) audit licence
• Jersey audit licence
• Isle of Man audit licence
• Cayman Islands audit licence
• British Virgin Islands audit licence

These registrations allow the firm to support organisations operating across both the UK and key international financial centres.

Core Services

In addition to cyber security audit services, Acumon provides a range of services that support financial reporting and governance.

These include:

• cyber security audits and security control reviews
• technology risk and cyber governance assessments
• statutory external audit
• group and subsidiary audits
• Public Interest Entity (PIE) audits
• charity and not-for-profit audit
• internal audit and governance reviews
• risk management and compliance support

Cyber security audit work is often delivered alongside discussions with management and boards regarding cyber risk management, governance frameworks, information security controls and regulatory compliance.

Many organisations review their cyber security arrangements as they implement new technologies, respond to evolving cyber threats or strengthen governance and operational resilience.

Acumon works with businesses that are:

• strengthening cyber security governance
• reviewing information security controls
• managing technology and cyber risks
• preparing for regulatory compliance requirements
• improving operational resilience

Early engagement can help ensure that cyber security controls, governance arrangements and risk management processes remain aligned with business objectives.

Contact Information

• Website: acumon.com
• Email: mail@acumon.com
• Address: 1-2 Craven Road, Ealing, London, W5 2UA, UK
• Phone: 020 8567 3451

BDO

BDO delivers cyber security services as part of their wider advisory practice, supporting organisations with assessing cyber risks, governance arrangements and security controls. Their cyber security audit work examines how prepared businesses are for evolving threats while reviewing areas such as regulatory compliance, technology risks and organisational resilience. The approach combines technical assessment with broader business and governance considerations.

Cyber security forms part of a wider digital advisory offering that covers strategy, implementation and ongoing management. Depending on an organisation’s requirements, reviews may extend to cloud governance, IT risk, system assurance and managed cyber security services. Their international network also enables support for organisations operating across multiple jurisdictions.

Key Highlights:

• UK advisory firm with dedicated cyber security practice
• Cyber security integrated with wider risk advisory services
• Reviews covering governance, controls and compliance
• Experience across multiple industries
• Access to international cyber security expertise
• Cyber strategy, implementation and managed services

Services:

• Cyber security audits
• Cyber risk assessments
• Cyber strategy and governance reviews
• Cloud governance assessments
• IT risk diagnostics
• System implementation assurance
• Managed cyber security services
• Data, analytics and AI security services

Contact Information

• Website: www.bdo.co.uk
• Instagram: www.instagram.com/lifeatbdo
• Address: Bridgewater House, Finzels Reach, Counterslip, Bristol, BS1 6BX, United Kingdom
• Phone: 0117 930 1500

PwC

PwC approaches cyber security as part of a wider business resilience strategy, combining technical security with governance, risk management and organisational change. Their cyber security audit capabilities sit within a broader advisory practice that supports organisations in understanding cyber risk, assessing existing controls and strengthening resilience across complex technology environments. Reviews may cover security strategy, operational processes, digital transformation initiatives and incident preparedness.

For organisations operating across multiple systems or jurisdictions, cyber security audits often form part of a wider assurance programme. Assessments are designed to help leadership understand where cyber risks exist, how security controls perform in practice and where improvements may be needed to support ongoing business objectives. Their wider cyber offering extends from strategic planning through to managed services and incident response.

Key Highlights:

• Cyber security audits within a broader advisory practice
• Focus on cyber resilience, governance and risk management
• Assessments supporting digital transformation programmes
• Reviews covering security strategy and operational controls
• Cyber services across multiple industries
• Advisory, managed services and incident response capabilities

Services:

• Cyber security audits
• Cyber security strategy reviews
• Cyber risk assessments
• Security governance reviews
• Managed cyber security services
• Incident response and recovery
• Cyber security design and implementation
• Security assurance and resilience assessments

Contact Information

• Website: www.pwc.co.uk
• Facebook: www.facebook.com/PwCUK
• LinkedIn: www.linkedin.com/company/pwc-uk
• Instagram: www.instagram.com/pwc_uk
• Address: 1 Embankment Place, London, WC2N 6RH, United Kingdom
• Phone: +44 (0)20 7583 5000

Deloitte

Deloitte provides cyber security services that help organisations review security risks alongside wider business transformation and technology change. Their audit and assessment work examines cyber resilience, enterprise security and governance, giving organisations a clearer understanding of how existing controls support operational and regulatory requirements. The focus extends beyond technical vulnerabilities to include long-term resilience and digital trust.

As cyber risks continue to evolve, many organisations need assessments that align security with business priorities. Their cyber practice covers advisory, operational security and privacy services, allowing organisations to evaluate security programmes, strengthen governance and prepare for emerging technology challenges across different sectors.

Key Highlights:

• Cyber security integrated with business transformation
• Governance and resilience-focused assessments
• Enterprise-wide cyber security capabilities
• Support across regulated and commercial sectors
• Digital trust and privacy expertise
• Global cyber advisory network

Services:

• Cyber security audits
• Cyber resilience assessments
• Cyber strategy and transformation
• Enterprise security reviews
• Digital trust and privacy assessments
• Managed cyber operations
• Cyber defence services
• Security governance consulting

Contact Information

• Website: www.deloitte.com
• Facebook: www.facebook.com/deloitteuk
• Twitter: x.com/deloitteuk
• LinkedIn: www.linkedin.com/company/deloitte
• Address: 1 New Street Square, London, EC4A 3HQ, United Kingdom
• Phone: +44 (0)20 7936 3000

EY

EY provides cyber security services centred on helping organisations understand and manage cyber risk across technology, data and business operations. Their audit-related work forms part of a wider cyber risk, compliance and resilience offering, covering areas such as identity management, privacy, threat management and security transformation. Assessments are intended to support informed decision-making while strengthening organisational resilience.

Many organisations use cyber security audits as part of wider governance and compliance programmes, particularly when adopting new technologies or responding to changing regulatory expectations. Alongside technical reviews, their services address operational processes, cyber maturity and risk management, giving businesses a broader view of how security supports long-term organisational objectives.

Key Highlights:

• Cyber security integrated with risk and compliance services
• Focus on organisational resilience and governance
• Assessments supporting digital transformation
• Cyber maturity and risk evaluation
• Privacy and identity management expertise
• Broad cyber advisory capabilities

Services:

• Cyber security audits
• Cyber risk and compliance assessments
• Cyber resilience reviews
• Identity and access management
• Data protection and privacy assessments
• Cybersecurity transformation
• Threat management and response
• Security architecture reviews

Contact Information

• Website: www.ey.com
• Facebook: www.facebook.com/pages/Ernst-Young/195665063800329
• LinkedIn: www.linkedin.com/company/1073
• Address: 1 More London Place, London SE1 2AF
• Phone: +44 20 7951 2000

KPMG

KPMG provides cyber security services that combine risk management, governance and technical security to help organisations understand and strengthen their cyber resilience. Their audit-related work reviews security controls, organisational processes and cyber strategy, giving businesses a clearer view of how well their security arrangements support operational and regulatory requirements. Assessments are often linked to broader transformation and resilience programmes across the organisation.

Cyber security audits are used to identify gaps, measure the effectiveness of existing controls and support future improvements. Alongside technical security reviews, their teams advise on areas such as identity management, operational technology, cyber defence and incident response, allowing organisations to build a more structured approach to cyber risk.

Key Highlights:

• Cyber security integrated with governance and risk advisory
• Focus on organisational resilience and security strategy
• Reviews covering technical and operational controls
• Support for regulated and complex business environments
• Cyber services across multiple industries
• Audit and advisory capabilities within a wider consulting practice

Services:

• Cyber security audits
• Cyber risk assessments
• Security governance reviews
• Cyber resilience assessments
• Identity and access management
• Cyber defence services
• Incident response planning
• Data privacy and protection reviews

Contact Information

• Website: kpmg.com
• Twitter: x.com/kpmguk
• LinkedIn: www.linkedin.com/company/kpmg-uk
• Address: 1 Marischal Square, Broad Street, Aberdeen, AB10 1DD
• Phone: +44 (0)1224 591 000

Armstrong Watson

Armstrong Watson offers cyber security services that help organisations assess risks, improve security controls and meet compliance requirements. Their cyber security audit work examines systems, vulnerabilities and organisational processes, giving businesses an independent view of their current security posture. Reviews are supported by practical recommendations that can help organisations strengthen resilience without adding unnecessary complexity.

Many of their services are aimed at organisations that do not have extensive in-house cyber security resources. Alongside security assessments, they provide support with compliance, employee awareness and incident planning, making cyber security part of wider business governance and risk management.

Key Highlights:

• Cyber security advisory for businesses and not-for-profit organisations
• Independent cyber security assessments
• Compliance-focused security reviews
• Employee awareness and cyber resilience support
• Cyber Essentials readiness guidance
• Risk-based approach to security improvement

Services:

• Cyber security audits
• Risk assessments
• Vulnerability scanning
• Cyber health checks
• Compliance reviews
• Cyber Essentials readiness
• Phishing simulation
• Incident response planning

Contact Information

• Website: www.armstrongwatson.co.uk
• Email: help@armstrongwatson.co.uk
• Facebook: www.facebook.com/armstrongwatson
• Twitter: x.com/armstrongwatson
• LinkedIn: www.linkedin.com/company/armstrong-watson
• Instagram: www.instagram.com/armstrongwatsonllp
• Address: Montgomery Way, Rosehill, Carlisle, CA1 2UU
• Phone: 0808 144 5575

Irwin Mitchell

Irwin Mitchell provides cyber security assessments that combine technical review with legal and regulatory expertise. Their audit process is designed to help organisations understand where cyber risks exist, assess current controls and identify practical actions that improve security and reduce exposure to data-related risks. Reviews begin with an assessment of the organisation’s environment before moving to a structured evaluation of key security areas.

Because cyber security is closely connected with data protection and regulatory compliance, assessments are supported by specialists with experience in governance and GDPR requirements. Audit findings are presented in a formal report that prioritises recommendations and gives organisations a clearer basis for future security planning.

Key Highlights:

• Cyber security assessments supported by legal expertise
• Focus on governance and data protection
• Structured audit methodology
• Practical recommendations for risk reduction
• GDPR and regulatory compliance support
• Suitable for organisations without dedicated cyber teams

Services:

• Cyber security audits
• Cyber risk assessments
• Security reviews
• GDPR compliance support
• Data protection assessments
• Security reporting
• Governance reviews
• Cyber security consultancy

Contact Information

• Website: www.irwinmitchell.com
• Facebook: www.facebook.com/irwinmitchellsolicitors
• Twitter: x.com/irwinmitchell
• LinkedIn: www.linkedin.com/company/irwin-mitchell
• Instagram: www.instagram.com/irwin_mitchell
• Address: 7th and 9th Floor, The Colmore Building, 20 Colmore Circus, Birmingham, B4 6AH
• Phone: 08082718429

Forvis Mazars

Forvis Mazars deliver cyber security audit and consulting services that help organisations assess cyber risk, strengthen governance and improve resilience across technology environments. Their reviews cover both internal and external security risks, examining how policies, technical controls and operational processes support compliance and day-to-day security management. Audit work can be aligned with recognised standards and adapted to suit organisations at different stages of their cyber security journey.

Many organisations use these assessments to prepare for certification, improve supplier assurance or gain a clearer understanding of their security maturity. Alongside audit services, they provide technical testing, privacy assessments and business continuity reviews, helping organisations develop a structured approach to cyber risk and regulatory compliance.

Key Highlights:

• Cyber security audits aligned with recognised frameworks
• Governance, compliance and resilience focus
• Security maturity and risk assessments
• Technical and organisational security reviews
• Support for certification readiness
• Privacy and data protection expertise

Services:

• Cyber security audits
• Cyber risk assessments
• Cyber security maturity assessments
• Vulnerability assessments
• Penetration testing
• Privacy and data protection audits
• Security architecture reviews
• Business continuity and resilience assessments

Contact Information

• Website: www.forvismazars.com
• Facebook: www.facebook.com/ForvisMazarsGroup
• Twitter: x.com/ForvisMazarsGR
• LinkedIn: www.linkedin.com/company/forvis-mazars-group
• Instagram: www.instagram.com/ForvisMazarsGroup
• Address: 30 Old Bailey, London, EC4M 7AU, United Kingdom
• Phone: +44 (0) 20 7063 4000

RSM UK

RSM UK positions cyber risk as a business governance issue as well as a technical challenge, helping organisations understand how cyber security affects operational resilience and decision-making. Their cyber advisory services support boards, executives and operational teams by reviewing governance arrangements, cyber risks and organisational preparedness. Cyber security audits contribute to this wider approach by identifying gaps in controls and supporting more informed risk management.

Board oversight, regulatory expectations and business continuity all influence how organisations approach cyber security today. Their services reflect this wider perspective, combining governance reviews with practical assessments that help organisations strengthen resilience, improve oversight and respond more effectively to changing cyber risks.

Key Highlights:

• Cyber security linked to governance and operational resilience
• Board and executive cyber risk support
• Focus on organisational preparedness
• Risk-based cyber security assessments
• Governance and resilience expertise
• Advisory services for business leaders

Services:

• Cyber security audits
• Cyber risk assessments
• Governance reviews
• Cyber resilience assessments
• Security control reviews
• Operational resilience consulting
• Risk management advisory
• Cyber security strategy support

Contact Information

• Website: www.rsmuk.com
• LinkedIn: www.linkedin.com/company/rsm-uk
• Instagram: www.instagram.com/rsm.uk
• Address: 4th Floor, The Capitol, 431 Union Street,Aberdeen, AB11 6DA
• Phone: +44 (0)1224 321133

Crowe

Crowe views cyber security audits as part of a wider approach to organisational resilience, combining technical assessments with governance, risk management and incident preparedness. Their reviews examine systems, networks, applications and security controls to identify vulnerabilities before they can be exploited, while helping organisations understand how existing practices align with regulatory expectations and business objectives.

Beyond identifying security weaknesses, the focus extends to improving readiness across the organisation. Audit findings are supported by practical recommendations that can guide future security planning, strengthen board oversight and improve the ability to respond to cyber incidents with less disruption to day-to-day operations.

Key Highlights:

• Cyber security audits linked to governance and resilience
• Technical and organisational security assessments
• Focus on regulatory compliance
• Incident preparedness and response planning
• Supply chain security reviews
• Employee awareness support

Services:

• Cyber security audits
• Cyber governance reviews
• Vulnerability assessments
• Penetration testing
• Supply chain security assessments
• Incident response planning
• Disaster recovery and business continuity reviews
• Cyber security awareness training

Contact Information

• Website: www.crowe.com
• Email: michael.jayson@crowe.co.uk
• Twitter: x.com/CroweUK
• LinkedIn: www.linkedin.com/company/crowe-uk
• Instagram: www.instagram.com/crowe_uk
• Address: 3rd Floor, St George’s House, 56 Peter Street, Manchester M2 3NQ
• Phone: +44 (0)161 214 7500

Moore Kingston Smith

Moore Kingston Smith provides cyber security services that help organisations assess cyber risk while supporting wider business resilience and governance. Their approach uses a cyber security maturity framework to review current security arrangements, identify areas for improvement and measure progress over time. Cyber security audits are designed to give organisations a structured understanding of how well critical systems, data and services are protected.

Different organisations face different security challenges, so assessments are adapted to suit operational priorities, regulatory requirements and business goals. Audit outcomes are intended to support informed decision-making, strengthen oversight and provide boards with greater visibility of cyber risks across the organisation.

Key Highlights:

• Cyber security maturity assessment framework
• Governance and resilience-focused reviews
• Risk-based cyber security assessments
• Support for boards and senior management
• Technical and advisory cyber services
• Certification and assurance capabilities

Services:

• Cyber security audits
• Cyber risk assessments
• Security maturity reviews
• Technical security assessments
• Certification readiness support
• Managed cyber security services
• Cyber security advisory
• Third-party assurance

Contact Information

• Website: mooreks.co.uk
• Twitter: x.com/MooreKSLLP
• LinkedIn: www.linkedin.com/company/moore-kingston-smith
• Address: 6th Floor, 9 Appold Street, London, EC2A 2AP
• Phone: +44 (0)20 4582 1000

PKF Littlejohn

PKF Littlejohn delivers cyber security services that focus on assessing cyber risk, improving security programmes and supporting operational resilience. Their cyber security audit capabilities form part of a broader technology advisory practice, helping organisations review existing controls, identify security gaps and establish practical priorities for improvement. Assessments can be tailored to match different business environments and levels of cyber maturity.

Where organisations need to strengthen long-term resilience, audit findings can feed into wider remediation planning, incident preparedness and supply chain risk management. Support extends beyond technical controls to include governance, employee awareness and operational processes, providing a balanced view of cyber security across the business.

Key Highlights:

• Risk-based cyber security audit approach
• Cyber security and operational resilience expertise
• Security programme assessments
• Incident response preparedness
• Supply chain risk management support
• Cyber awareness and governance services

Services:

• Cyber security audits
• Cyber risk assessments
• Security programme reviews
• Incident response planning
• Supply chain risk assessments
• Cyber remediation support
• Cyber security awareness training
• Information security advisory

Contact Information

• Website: www.pkf-l.com
• Email: info@pkf-l.com
• Twitter: x.com/PKF_Littlejohn
• LinkedIn: www.linkedin.com/company/littlejohn
• Instagram: www.instagram.com/pkf.littlejohn
• Address: 30 Churchill Place, London, E14 5RE
• Phone: +44 (0)20 7516 2200

Conclusion

The right cyber security audit service depends on your organisation’s size, industry and regulatory requirements. Some providers focus on technical security reviews, while others combine cyber security with governance, risk management and compliance. The scope of an audit can also vary, from a high-level assessment to a detailed review of policies, processes and technical controls.

When comparing providers, it is worth looking at the audit methodology, the standards and frameworks they assess against, the level of detail included in their reports and whether they offer support after the audit has been completed. A clear report with practical recommendations is often just as valuable as the assessment itself, as it helps organisations prioritise improvements and plan future security work.

This guide highlights a selection of cyber security audit firms operating in the UK, each with different areas of expertise. Reviewing their services alongside your own business needs can help you identify a provider whose approach, experience and audit scope are the best fit for your organisation.