Blog · 2026-03-09 · manager

Best IT Audit Services Companies in London: Who to Consider

London has no shortage of firms offering IT audit support. From global consultancies with large risk teams to smaller specialists who focus purely on technology assurance, the range can feel a bit overwhelming at first glance. Some organisations need a full-scale IT risk review tied to regulatory compliance. Others just want a second pair of […]

This article brings together a curated list of IT audit services companies in London. It is not about bold claims or glossy marketing language. Instead, the focus is on what these firms actually do – how they approach IT risk, internal controls, cybersecurity reviews, and regulatory requirements. Whether you are a fast-growing fintech, a public sector body, or an established enterprise trying to tighten governance, this list should help you see the landscape a little more clearly.

1. Acumon

At Acumon we provide IT audit and risk assurance as part of our wider audit, tax and advisory work. We are a registered audit firm and support UK PLCs, limited companies, charities and international subsidiaries with structured external audits and internal reviews. Alongside financial audit, we carry out risk and technology assurance work for CFOs and finance leaders, covering IT risk, cybersecurity oversight, governance and compliance. We look at how systems are controlled, how risks are managed and how technology supports reporting and decision-making. Our approach is practical and tied closely to the real operational side of a business, not just paperwork.

We are based in West London and work with organisations across London and the wider UK. For businesses in London looking for IT audit services, we combine financial audit discipline with technology risk insight, which helps link IT controls back to overall governance and regulatory expectations. Our UK-based team works directly with clients, whether on-site or remotely, and our risk and tech assurance work supports London businesses that need clarity around compliance, system controls and internal audit requirements.

Key Highlights:

Registered audit firm in the UK
UK-based team of accountants and risk professionals
Risk and tech assurance services for finance leaders
Experience with PLCs, charities and group subsidiaries
Integrated audit, tax and advisory offering

Services:

External audit
IT risk and cybersecurity reviews
Governance and compliance support
Internal audit
Accounts and bookkeeping
Tax planning and compliance
Payroll services
Company secretarial support

Contact information:

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

2. Sonar IT

Sonar IT focuses on IT audit and compliance services designed mainly for small to mid-sized organisations. Their work looks closely at system visibility, data access, patching, endpoint security and overall IT hygiene. Instead of treating an audit as a formality, they carry out detailed reviews of user accounts, devices, software compliance and system health. The result is usually a clear report that outlines what is secure, what is outdated and where gaps sit. They also support businesses in addressing findings rather than leaving them with a list of problems.

Sonar IT operates from London and provides IT auditing services to businesses across the city. For companies facing regulatory pressure or insurance requirements, their audits help clarify compliance status and highlight practical next steps. London organisations with smaller internal IT teams often rely on this type of external review to understand where their risks lie and how to tighten controls without overcomplicating their setup.

Key Highlights:

IT audit and compliance focus
Reviews covering data security and user access
Use of established security and monitoring tools
Support for small and mid-sized teams
Ongoing review and follow-up support

Services:

IT compliance audits
Cybersecurity risk assessments
User access and account reviews
Patch and update assessments
Endpoint security checks
Ongoing IT support and reviews

Contact information:

Website: www.sonarit.co.uk
Phone: 0203 011 0805
E-mail: ontheradar@sonarit.co.uk
Address: 124 City Rd, London EC1V 2NX, United Kingdom
Facebook: www.facebook.com/SonarITLtd
Linkedin: www.linkedin.com/company/28519584

3. Ghost Enterprises

Ghost Enterprises provides IT audits as part of its managed IT and cybersecurity services. Their audits are carried out by in-house cybersecurity consultants who assess infrastructure, system performance and compliance. The focus is on identifying weaknesses, reviewing technical efficiency and aligning IT systems with business goals. An audit can cover compliance, reliability, procurement processes and overall infrastructure effectiveness. The aim is to define a clearer IT strategy based on how systems are actually functioning.

Ghost Enterprises lists London among the areas they serve and works with businesses in the city. For London organisations planning growth or reviewing their internal controls, their IT audit service helps evaluate whether existing infrastructure can support future plans. By linking cybersecurity, workflow efficiency and compliance into one review, they provide a structured way for businesses to understand how well their IT environment is supporting day-to-day operations.

Key Highlights:

In-house cybersecurity consultants
Focus on infrastructure effectiveness
IT audits aligned with business strategy
Coverage of compliance and operational efficiency
Serves London and surrounding areas

Services:

IT infrastructure audits
Cybersecurity assessments
Compliance reviews
IT strategy development
Managed IT services
Cloud and consultancy support

Contact information:

Website: ghostenterprises.co.uk
Phone: 01245 208080
E-mail: info@ghostenterprises.co.uk
Address: The Old Grange, Warren Estate, Lordship Road, Writtle, Essex, CM1 3WT
Facebook: www.facebook.com/Ghost.Enterprises
Twitter: x.com/ghostentltd
LinkedIn: www.linkedin.com/company/ghost-enterprises

4. Cardonet

Cardonet provides IT audit services for businesses in London as part of its wider IT consultancy and managed services work. They approach an IT audit as a review of how technology supports day to day operations, not just a checklist of systems. Their audits cover servers, desktops, networking, security, applications, licensing, hosting, backup, telephony and supplier arrangements. The aim is to give organisations a clearer view of how their IT setup fits with business plans, where gaps exist and what could be improved.

Based in London, Cardonet works with companies across the city that need an independent review of their technology environment. Their IT audit process includes discovery, analysis and recommendations, with interviews and both manual and automated checks. For London businesses dealing with growth, supplier complexity or performance issues, this type of structured review helps identify risks, compliance gaps and areas where systems are not aligned with operational needs.

Key Highlights:

London based IT services provider
Three phase IT audit approach
Review of infrastructure, security and suppliers
Gap analysis with practical recommendations
Option for regular IT audits

Services:

IT audits
IT consultancy
Managed IT services
Cyber security reviews
IT strategy advice
Backup and continuity planning
IT procurement and supplier management

Contact information:

Website: www.cardonet.co.uk
Phone: 02030342244
E-mail: hello@cardonet.co.uk
Address: 7 Stean Street, London, UK, E8 4ED
Facebook: www.facebook.com/Cardonet
Twitter: x.com/cardonetit
LinkedIn: www.linkedin.com/company/cardonet

5. Ava Tech

Ava Tech delivers IT audit services focused on security, compliance and system reliability. Their audits assess technology infrastructure, controls within business processes and adherence to internal policies. The work includes reviewing security controls, resilience of disaster recovery plans, access controls and third party dependencies. They also assess alignment with recognised standards such as ISO 27001, COBIT and GDPR where relevant. The outcome is a structured report with findings and recommendations for improvement.

Operating from London, Ava Tech supports organisations across sectors that need a clearer understanding of their IT risks and control environment. Their audit process follows defined stages, from planning and risk assessment through to reporting and follow up support. For London businesses managing regulatory pressure or looking to strengthen governance, their IT audit service provides an external review of systems and processes without interrupting daily operations.

Key Highlights:

Structured audit process with defined stages
Focus on security controls and compliance
Review of business continuity and disaster recovery
Industry specific audit experience
Post audit support available

Services:

IT audit services
Cybersecurity assessments
Compliance reviews
Risk assessments
Business continuity planning
Ongoing monitoring and support

Contact information:

Website: www.ava-tech.co.uk
Phone: 0203 9155 510
E-mail: info@ava-tech.co.uk
Address: 20-22 Wenlock Road, London, N1 7GU

6. Azets

Azets provides audit and assurance services across a wide range of sectors. While their work is often associated with statutory and external financial audit, they also offer risk assurance and internal audit services that extend into technology controls and governance. Their approach focuses on identifying risks, reviewing processes and providing independent insight into how systems and controls are operating. The aim is to support informed decision making and strengthen overall assurance frameworks.

With offices across the UK, including London, Azets supports mid market businesses, private equity backed organisations and public sector bodies. For London companies requiring IT audit related assurance within a broader audit framework, their risk assurance and internal audit services help evaluate control environments and operational risks. Their structure combines local contacts with national resources, which can be relevant for organisations operating across multiple locations.

Key Highlights:

National audit and assurance provider
Risk assurance and internal audit services
Sector specific audit experience
Local London presence
Focus on control environments and risk

Services:

External audit
Risk assurance
Internal audit
Statutory accounting
Corporate finance
Tax and advisory services

Contact information:

Website: www.azets.com
Phone: +44 (0) 20 7403 1877
Address: London, 2nd Floor, Regis House, 45 King William Street, EC4R 9AN
LinkedIn: www.linkedin.com/company/azets
Instagram: www.instagram.com/azets_uk

7. Moore Kingston Smith

Moore Kingston Smith provides audit and assurance services to a wide range of organisations, including private companies, listed businesses, PE backed firms and public interest entities. Their audit work covers different reporting frameworks such as IFRS, UK GAAP and US GAAP. Alongside corporate audit, they support financial reporting, nonprofit reporting and royalty audits. Technology also plays a role in their methodology, with data analytics and audit tools used to review information and strengthen the assurance process.

With a strong presence in London and part of Moore Global, they work with businesses that operate locally and internationally. For organisations in London looking at IT audit services within a broader assurance framework, their audit technology and compliance risk capabilities link financial reporting with system controls and data oversight. This can be relevant where IT environments directly affect reporting accuracy, governance and regulatory compliance.

Key Highlights:

Corporate audit across multiple reporting standards
Use of audit technology and data analytics
Experience with private, listed and PE backed businesses
Part of an international network
Sector specific audit teams

Services:

Corporate audit
Financial reporting support
Nonprofit reporting
Royalty audits
Audit technology
Technology and compliance risk
Third party assurance

Contact information:

Website: mooreks.co.uk
Phone: +44 (0)20 4582 1000
Twitter: x.com/MooreKSLLP
LinkedIn: www.linkedin.com/company/moore-kingston-smith

8. Protiviti

Protiviti focuses on internal audit and risk advisory services, including technology audit and controls advisory. Their work looks at IT risk, governance and compliance objectives, with teams that support organisations through outsourced, co sourced or staff augmentation models. Technology audit forms a core part of their offering, helping businesses identify and assess key technology risks and evaluate control frameworks. They also advise on audit transformation, data driven audit methods and the use of automation.

Operating in London as part of a global consulting firm, Protiviti supports organisations facing complex regulatory and operational demands. For London companies requiring IT audit services that go beyond basic compliance, their internal audit solutions integrate technology risk, SOX compliance, fraud risk management and controls testing. This approach links IT controls to wider business and regulatory requirements, particularly in sectors where risk management and governance are closely monitored.

Key Highlights:

Internal audit and technology audit focus
Support through outsourced and co sourced models
Controls and compliance advisory
SOX compliance experience
Global delivery capability with London presence

Services:

Technology audit
Internal audit outsourcing
Controls advisory
SOX compliance support
Fraud risk management
Audit transformation
Capital project consulting

Contact information:

Website: www.protiviti.com
Phone: +44.20.7930.8808
Address: The Shard, 32 London Bridge St, London SE1 9SG, United Kingdom
Facebook: www.facebook.com/Protiviti
Twitter: x.com/ProtivitiUK
LinkedIn: www.linkedin.com/company/protiviti-uk-
Instagram: www.instagram.com/protiviti.uk

9. Grant Thornton

Grant Thornton delivers internal audit services as part of its business risk advisory practice. Their approach is risk based and designed to provide independent assurance and challenge around controls and governance. They work with organisations of different sizes and levels of complexity, offering co source, outsource or loan staff arrangements. Their internal audit teams often integrate subject matter experts to address emerging risks and regulatory expectations.

With a significant presence in London, Grant Thornton supports financial services firms, public sector bodies and other regulated organisations. For London businesses considering IT audit services within a broader internal audit function, their technology risk and internal audit specialists review control environments, emerging risks and compliance requirements. This can include evaluating how technology risks are managed and whether internal audit frameworks remain effective in a changing regulatory climate.

Key Highlights:

Risk based internal audit approach
Co source, outsource and staff support models
Integration of subject matter experts
Technology risk capability
Strong London office presence

Services:

Internal audit services
Technology risk reviews
External quality assessments
Controls testing
Financial services internal audit
Business risk advisory

Contact information:

Website: www.grantthornton.co.uk
Phone: +44 (0)20 7383 5100
Address: 8 Finsbury Circus, London, EC2M 7EA
LinkedIn: www.linkedin.com/company/grant-thornton-uk
Instagram: www.instagram.com/gt_trainees

10. MMBA

MMBA is a London based accountancy firm providing statutory and non-statutory audit services alongside tax and advisory work. Their audit services include external audits, compliance audits and internal audits. They follow a structured audit process covering planning, risk assessment, control evaluation and reporting. While their core focus is financial audit, their services also extend to internal control reviews and regulatory audits in sectors such as financial services and education.

With offices in London, they work with small and medium sized businesses as well as larger organisations. For companies in London considering IT audit services within a financial audit framework, MMBA’s internal audit and compliance reviews may include testing of internal controls and systems that support financial reporting. Their audit approach links regulatory compliance with operational processes, which can involve reviewing how systems are managed and documented.

Key Highlights:

London based audit and accountancy firm
Statutory and non-statutory audit services
Structured audit methodology
Experience with regulatory audits
Internal control testing as part of audits

Services:

Statutory audit
External audit
Internal audit
Compliance audit
Financial statement audit
Due diligence audits
Forensic and fraud examinations
Advisory and tax services

Contact information:

Website: www.mmba.co.uk
Phone: 0203 355 0841
E-mail: info@mmba.co.uk
Address: 16 Upper Woburn Place, Greater London, WC1H 0AF
Facebook: www.facebook.com/mmbaaccountants
Twitter: x.com/mmbaaccountants
LinkedIn: www.linkedin.com/company/mmba-accountants

11. RSM UK

RSM UK provides audit, tax and consulting services across a wide range of sectors. Their audit services form part of a broader assurance and risk offering, which includes risk and governance advisory. While the website overview focuses on financial audit, their services typically connect audit work with governance, fraud risk and business transformation. Audit engagements are designed to assess financial reporting and control environments within organisations of different sizes.

With multiple offices across the UK, including London, RSM works with mid market businesses and larger groups. For London organisations seeking IT audit services within a broader audit and risk context, their risk and governance teams support reviews of control frameworks and operational risks. This can include evaluating how technology risks are managed as part of overall assurance and compliance structures.

Key Highlights:

National audit and consulting firm
Audit and risk advisory services
Governance and control focus
Multi sector experience
London office presence

Services:

Audit services
Risk and governance advisory
Forensic and investigation services
Business transformation
Tax services
Consulting services

Contact information:

Website: www.rsm.global
Phone: +44 (0)20 3201 8000
Address: 25 Farringdon Street, London, EC4A 4AB
Facebook: www.facebook.com/GlobalRSM
Twitter: x.com/RSM_Global
LinkedIn: www.linkedin.com/company/rsm-uk
Instagram: www.instagram.com/rsm.uk

12. Zenith Audit

Zenith Audit is a London based audit firm with a strong focus on the financial services sector. They provide statutory and voluntary audits, group audits, internal audits and regulatory audits, including areas such as Solvency II, CASS and safeguarding. Their work is centred on assurance and compliance, with attention to regulatory expectations and sector specific rules. The leadership team brings experience from larger audit firms and regulatory environments, which shapes how they approach statutory and regulatory audit engagements.

For organisations in London operating in financial services, their audit services connect financial reporting with regulatory oversight and control frameworks. While they are primarily a financial audit firm, internal audit and regulatory reviews often involve assessing systems, controls and governance arrangements. This can overlap with IT controls where technology underpins client assets, reporting or safeguarding requirements.

Key Highlights:

London based registered audit firm
Specialist focus on financial services
Statutory and regulatory audit experience
Internal audit capability
Leadership with regulatory background

Services:

Statutory audits
Voluntary audits
Group audits
Internal audits
Regulatory audits including Solvency II and CASS
Agreed upon procedures
Reviews of financial information

Contact information:

Website: zenithaudit.co.uk
Phone: 020 3597 6825
E-mail: office@zenithaudit.co.uk
Address: 3rd Floor North, Warwick House, 65/66 Queen Street, London, England, EC4R 1EB
Facebook: www.facebook.com/zenithaudituk
LinkedIn: www.linkedin.com/company/zenith-audit-uk

13. S&W

S&W provides audit and assurance services as part of a broader accounting and advisory practice. Their audit work includes statutory and non-statutory audits, as well as specialist areas such as royalty and pension auditing. Alongside this, they offer risk advisory and regulatory consulting services, which address governance, controls and compliance. Their approach combines traditional audit methodology with tools and advisory input across different business functions.

With offices in London, S&W supports organisations across sectors that require assurance around financial reporting and risk management. For London businesses considering IT audit services within a wider assurance framework, their risk advisory and digital services teams review control environments, systems and cyber security challenges. This creates a link between financial audit, governance and technology oversight.

Key Highlights:

Audit and assurance services
Risk advisory and regulatory consulting
Digital and cyber security support
London office presence
Sector focused audit teams

Services:

Statutory and non-statutory audit
Risk advisory
Regulatory consulting
Digital services
Forensic services
Corporate finance and tax services

Contact information:

Website: www.swgroup.com
Phone: +44 204 617 55 00
Address: 45 Gresham St., London, EC2V 7BG
Twitter: x.com/S_W_Group
LinkedIn: www.linkedin.com/company/swgroupuk

14. Serveline

Serveline provides IT audit and compliance services as part of its managed security and IT support offering. Their audits focus on reviewing how IT systems are used, how data is protected and whether compliance requirements are being met. The process typically includes risk assessment, an IT compliance checklist and reviews of infrastructure, access controls and security arrangements. Their services are aimed mainly at small and medium sized businesses that need clarity around compliance and system effectiveness.

Although based outside central London, Serveline works with businesses across the UK, including London. For London organisations without large internal IT teams, their IT audit and compliance services provide an external review of systems and regulatory readiness. This type of support is often relevant where companies need to strengthen data security, prepare for audits or confirm that policies and controls are properly implemented.

Key Highlights:

Focus on IT audit and compliance
Risk assessment and compliance checklists
Support for SMEs
Managed security services provider
UK wide service coverage including London

Services:

IT compliance audits
Risk assessments
Security reviews
Managed IT services
Managed security services
IT consultancy

Contact information:

Website: www.serveline.co.uk
Phone: 01384 429 120
E-mail: hello@serveline.co.uk
Address: Serveline IT, KinverPoint Business Village, Cookley Lane, Kinver DY7 6NW
Twitter: x.com/servelineit
LinkedIn: www.linkedin.com/company/serveline-it-ltd

15. The Final Step

The Final Step provides IT audit services to small and medium sized businesses across London and Greater London. Their audits are positioned as a way to understand the current state of an organisation’s IT, covering security, productivity and overall IT maturity. They offer both strategic and technical audits, with an approach that includes ranking priorities and highlighting critical issues. The outcome is a report outlining key findings and recommended next steps, helping businesses see where improvements are needed.

Based in London, they work with companies that may be reviewing their current IT support arrangements or planning changes. Their audit process includes a high level review, a more strategic analysis aligned to business goals, budgeting guidance and an ongoing improvement plan. For London organisations that want clarity before switching providers or investing further in technology, their IT audit service acts as an independent assessment of systems and supplier performance.

Key Highlights:

IT audit services for SMEs and enterprises
Strategic and technical audit options
Priority ranking of issues
Independent review of existing IT providers
London and Greater London coverage

Services:

IT audits
Managed IT services
IT consultancy
Cyber security services
Cloud services
Business continuity and disaster recovery

Contact information:

Website: www.thefinalstep.co.uk
Phone: 020 7572 0000
E-mail: contact@thefinalstep.co.uk
Address: 35 Ballards Lane, London, N3 1XW, UK
Facebook: www.facebook.com/thefinalstepit
Twitter: x.com/thefinalstepIT
LinkedIn: www.linkedin.com/company/the-final-step

16. EY

EY delivers audit services as part of its global assurance practice. Their audits focus on financial reporting, regulatory compliance and stakeholder confidence, supported by digital audit tools and data analytics. Multidisciplinary teams combine accounting expertise with technology capabilities, particularly in areas such as digital audit and complex reporting environments. The firm emphasises consistency in methodology while adapting to evolving regulatory and market expectations.

With a significant presence in London, EY works with large and complex organisations across sectors including banking, capital markets and technology. For London businesses requiring IT audit services within a broader assurance framework, EY’s digital audit approach integrates technology risk, data analysis and system level review into financial audit engagements. This can include evaluating how digital systems, automation and emerging technologies affect reporting and governance.

Key Highlights:

Global audit and assurance practice
Digital audit methodology
Multidisciplinary audit teams
Focus on regulatory and reporting standards
London office presence

Services:

External audit
Digital audit
Financial accounting advisory
Risk assessment and compliance support
Industry specific audit services

Contact information:

Website: www.ey.com
Address: EY 6 More London Place London SE1 2DA
Facebook: www.facebook.com/EY
Twitter: x.com/EYnews
LinkedIn: www.linkedin.com/company/ernstandyoung

17. Advantage Business Systems Limited

Advantage Business Systems Limited provides IT audit services as part of its managed IT offering in London. Their audits review hardware, software, policies, processes and supplier arrangements. The process includes stakeholder interviews, automated system checks, evaluation of IT processes and a final report with recommendations. The aim is to identify inefficiencies, security weaknesses and areas where systems may not be aligned with business needs.

Operating from London, Advantage works mainly with small and medium sized businesses. Their IT audit services are often used as a practical check on system health, covering areas such as Microsoft 365 setup, software licensing and disaster recovery planning. For London companies looking to review performance, security or supplier contracts, their audits provide a structured overview of current infrastructure and operational risks.

Key Highlights:

London based managed IT provider
Five step IT audit process
User, system and supplier evaluation
Office 365 and software licence audits
Focus on SMEs

Services:

IT audits
Office 365 audit
Software licence audit
Managed IT services
IT consultancy
Microsoft solutions and cloud services

Contact information:

Website: www.advantage.co.uk
Phone: 020 3813 5096
E-mail: hello@advantage.co.uk
Address: The White Chapel Building, 1st Floor, 10 Whitechapel High Street, London, E1 8QS
Facebook: www.facebook.com/people/Advantage-Business-Systems
Twitter: x.com/DynamicsABS
LinkedIn: www.linkedin.com/company/advantage-business-systems-limited

Conclusion

London has no shortage of firms offering IT audit services, but they do not all approach the work in the same way. Some sit firmly in the financial audit world and bring technology risk into a wider assurance framework. Others focus purely on IT systems, compliance and cyber security for smaller teams that just need clarity and direction. That difference matters more than most people realise.

In practice, the right choice often comes down to what you are actually trying to solve. Are you meeting a regulatory requirement, preparing for growth, reviewing internal controls, or simply checking whether your current IT setup makes sense? An IT audit should not feel like a formality. It should give you a clearer picture of how your systems support the business, where the weak spots are, and what realistically needs attention.

London businesses operate in a fast moving, highly regulated environment. Technology underpins almost everything now, from financial reporting to client data handling. Taking the time to step back and review it properly is rarely wasted effort. If anything, it is one of those things that feels optional until it suddenly is not.