Choosing Tax Investigation Support in the UK: Companies Overview
AC
Acumon Chartered Accountants·14 min read
Dealing with a tax investigation is rarely straightforward. Whether it’s a routine enquiry or something more complex, the process can quickly become time-consuming, technical, and, at times, stressful.
Across the UK, there’s a wide mix of firms that support businesses and individuals through these situations. Some are large advisory networks with dedicated dispute teams, while others are smaller specialist practices focused specifically on tax investigations and HMRC enquiries. The way they approach cases, and the type of clients they typically work with, can vary quite a bit.
This guide brings together a selection of tax investigation services companies operating in the UK. It’s not intended as a ranking or endorsement. Instead, the aim is to give a clearer sense of the landscape: who these firms are, the kind of support they provide, and how their services are typically positioned.
Acumon
Acumon is a UK firm of chartered accountants and tax advisors providing representation in HMRC tax investigations, enquiries and disputes.
The firm supports individuals, businesses and corporate groups in managing HMRC enquiries, from initial notification through to resolution, including settlement negotiations and, where required, formal appeals.
Work includes assessment of HMRC enquiries, development of structured response strategies, preparation of supporting documentation and direct engagement with HMRC throughout the investigation process.
Many members of the tax team have previously worked within HMRC, providing practical insight into investigation procedures, risk assessment, negotiation approach and penalty frameworks.
The firm also supports voluntary disclosures and complex investigation scenarios, including Code of Practice 9 (COP9) and Contractual Disclosure Facility (CDF) cases, where careful handling and structured negotiation are required.
Tax investigation services are delivered as part of a broader tax offering, particularly where enquiries involve multiple tax regimes such as corporation tax, VAT and employment taxes.
Tax Investigation Capabilities
Acumon provides tax investigation services across a range of HMRC enquiry types.
These include:
full enquiries covering multiple tax years
aspect enquiries focused on specific issues
random enquiries and compliance checks
Code of Practice 9 (COP9) investigations
Contractual Disclosure Facility (CDF) cases
VAT investigations
PAYE and employment tax investigations
corporation tax enquiries
Engagements are structured around the nature and scope of the HMRC enquiry.
Regulatory Licences and Registrations
Acumon operates within UK tax and regulatory frameworks and holds a number of audit registrations that support its work 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 enable the firm to support organisations operating across both UK and international environments, in line with regulatory and professional requirements.
Core Services
Alongside tax investigation and dispute resolution work, Acumon delivers a range of services that support financial oversight, governance and regulatory compliance.
These include:
statutory external audit
group and subsidiary audits
Public Interest Entity (PIE) audits
charity and not-for-profit audit
audit of international group structures
internal audit and governance reviews
risk management and compliance support
Engagements are typically supported by discussions with management and stakeholders around reporting approaches, governance arrangements and control environments.
As organisations develop, they often become subject to more complex reporting and compliance expectations linked to their size, structure or regulatory position.
Acumon works with businesses that are:
establishing structured reporting and governance frameworks
preparing for investment or funding activity
entering or expanding into international markets
operating across group or multi-entity structures
Early involvement helps ensure that systems, documentation and internal processes are aligned with regulatory expectations and business requirements.
Address: 1-2 Craven Road, Ealing, London, W5 2UA, UK
Phone: 020 8567 3451
Saffery
Saffery handle tax investigations across a mix of individual and corporate clients, often where affairs are more complex or involve international elements. Their work frequently includes dealing with detailed HMRC enquiries where technical interpretation plays a central role, particularly around areas like residence, overseas income or relief claims.
In some cases, the focus is on clarifying specific points in a return, while in others it involves managing full investigations under formal HMRC procedures. When past errors come to light, they guide clients through disclosure options and help structure communication with HMRC in a way that keeps the process clear and controlled.
Key Highlights:
Experience with complex and international tax matters
Work across multiple tax types including income tax and VAT
Involvement in formal HMRC investigations such as COP8 and COP9
Address: Midland House, 2 Poole Road, Bournemouth, Dorset BH2 5QY, UK
Phone: +44 (0)1202 204744
AAB
AAB provide tax investigation and dispute resolution support for individuals, businesses and organisations across different sectors. Their work covers a broad range of HMRC enquiries, from routine compliance checks to more complex investigations, including those involving offshore matters or suspected irregularities.
They guide clients through each stage of an enquiry, handling communication with HMRC and working to bring cases to a conclusion within a reasonable timeframe. Their team includes professionals with experience both advising clients and working within HMRC, which influences how they approach negotiations and risk assessment.
Key Highlights:
Support across a wide range of HMRC investigations
Experience with both domestic and offshore tax matters
Involvement in complex cases including COP9 enquiries
Background of team members includes HMRC experience
Focus on managing penalties and resolving disputes
Address: Gresham House, 5-7 St Paul's St, Leeds, LS1 2JG
Phone: +44 (0)113 297 6789
Alexander & Co
Alexander & Co support clients through different types of tax investigations, from routine checks to more serious enquiries involving detailed financial reviews. Their experience includes dealing with enquiries initiated by various HMRC departments, including specialist investigation units.
Part of their role is helping clients make sense of why an enquiry has been opened and what to expect next. They stay involved through negotiations and discussions with HMRC, particularly where tax liabilities and penalties are being reviewed or challenged.
Key Highlights:
Experience across a range of HMRC investigations
Work with both individuals and businesses
Involvement in complex and specialist enquiries
Support during negotiations with HMRC
Understanding of investigation triggers and timelines
Address: Centurion House, 129 Deansgate, Manchester, Greater Manchester M3 3WR
Phone: 0161 832 4841
Fusion Accountants
Fusion Accountants focus on supporting smaller businesses and individuals dealing with HMRC enquiries. Their involvement usually centres on taking over communication with HMRC and managing the practical side of the investigation so clients can stay focused on running their business.
A structured fee protection element sits alongside their investigation support, covering the cost of professional fees linked to enquiries. Day-to-day work often includes preparing responses, attending meetings with HMRC and ensuring that requests for information are handled properly.
Address: Ground Floor 90 Long Acre Covent Garden London WC2E 9RZ
Phone: 020 8577 0200
Gilbert Tax
Gilbert Tax specialise in tax investigations and tend to be involved where cases are more serious or have been ongoing for some time. Their work often includes stepping into situations where disclosure is required or where HMRC has raised concerns around potential irregularities.
They manage the process directly with HMRC and, where necessary, coordinate with legal advisers if a case progresses further. Some matters move towards tribunal when agreement cannot be reached, and their role then extends into preparing and presenting the case.
Address: 5 Flemming Court, Summit Park, Glasshoughton, WF10 5HW
Phone: 0800 011 9625
Armstrong Watson
Armstrong Watson provide a tax investigation service that is closely linked to fee protection arrangements. The structure is designed to cover the cost of dealing with HMRC enquiries, with support provided throughout the investigation once a claim is in place.
Their coverage includes a range of common enquiry types and disputes, including VAT and employer compliance matters. The service also extends to earlier stages such as information requests or compliance checks, where preparation can influence how an enquiry develops.
Key Highlights:
Tax investigation service combined with fee protection
Coverage across multiple HMRC enquiry types
Support during both enquiries and pre-dispute stages
Address: James Watson House, Montgomery Way, Rosehill, Carlisle, CA1 2UU
Phone: 0808 144 5575
Menzies LLP
Menzies LLP support individuals and businesses facing HMRC enquiries, taking on communication with HMRC and guiding clients through each stage of the process. Their involvement can range from relatively focused checks to broader investigations affecting multiple areas of tax.
They offer a subscription-based service that covers professional fees linked to enquiries, which changes how clients approach seeking advice when an issue arises. The scope of their work includes both standard compliance matters and more detailed investigations.
Key Highlights:
Support for individuals and businesses
Direct liaison with HMRC
Subscription-based fee protection model
Coverage across different enquiry types
Access to internal technical specialists
Services:
HMRC tax enquiries
Full and aspect investigations
VAT and PAYE disputes
IR35 enquiries
Business inspections
Code of Practice 8 investigations
Contact Information:
Website: www.menzies.co.uk
LinkedIn: www.linkedin.com/company/menzies-llp
Instagram: www.instagram.com/menzies_llp
Address: 4th Floor, 95 Gresham St, London EC2V 7AB
Phone: +44 (0)20 7387 5868
WLH Tax
WLH Tax focus entirely on tax investigations, which shapes how they handle HMRC enquiries across individuals, companies and offshore structures. Their work centres on dealing with complex cases, including those involving suspected fraud, disclosure requirements or cross-border issues. The scope of their involvement often depends on how serious the enquiry is, from standard compliance checks through to criminal investigations.
A noticeable part of their role is stepping in where specialist input is needed, including working alongside accountants or legal advisers who may not deal with investigations on a regular basis. They are involved in managing communication with HMRC, preparing disclosures and supporting cases that move towards tribunal or litigation.
Key Highlights:
Focus exclusively on tax investigations
Experience with serious and complex HMRC enquiries
Hazlewoods provide a tax investigation service that sits alongside their wider accountancy and tax work. The service is structured around supporting clients who are selected for HMRC enquiries, with the same advisers continuing to handle the matter since they already understand the client’s affairs.
The setup includes an insurance-backed element that covers professional fees linked to investigations. Once an enquiry begins, they take over communication with HMRC, attend meetings and manage the process through to resolution, keeping the client informed along the way.
Key Highlights:
Tax investigation service linked to existing client relationships
Representation by advisers familiar with client affairs
RPG Crouch Chapman offer a tax investigation service designed around fee protection and ongoing support during HMRC enquiries. Their service is subscription-based and backed by insurance, covering professional costs when an investigation is opened.
Alongside the investigation support, they provide access to additional resources such as business guidance tools, which sit alongside the core service. Their role during an enquiry includes advising on next steps and helping clients manage the process from start to finish.
Xeinadin provide a tax investigation service focused on covering professional fees when HMRC opens an enquiry. The service is designed to ensure clients have access to representation without needing to weigh up the cost of engaging advisers once an investigation begins.
Their involvement centres on defending the client’s position during the enquiry and ensuring that responses to HMRC are properly handled. The emphasis is on maintaining a structured approach to dealing with requests and challenges raised during the process.
Address: Becket House, 36 Old Jewry, Bank, London, EC2R 8DD
Phone: 0203 086 8677
Taylor Associates
Taylor Associates deal with tax investigations as part of their wider accountancy services, supporting businesses that are selected for HMRC enquiries. Their involvement typically includes taking control of communication with HMRC and guiding the client through each stage of the process.
Their service includes fee protection, which covers the cost of professional work linked to the investigation. They remain involved through to appeals where required, managing both the practical and technical aspects of the enquiry.
Key Highlights:
Support for businesses facing HMRC enquiries
Representation throughout investigation and appeal stages
Kreston Reeves approach tax investigations through a combination of dispute support and fee protection. Their service covers professional costs linked to HMRC enquiries, allowing them to remain involved from the initial contact through to resolution.
Their work includes handling different types of disputes, from standard enquiries to more technical cases involving residence, fraud concerns or formal HMRC procedures. They also support alternative dispute resolution and cases that proceed to litigation.
Key Highlights:
Coverage of professional fees during HMRC enquiries
Support from initial contact through to resolution
Experience across a range of tax disputes
Involvement in formal HMRC procedures
Access to legal and dispute resolution support
Services:
HMRC tax enquiries
Code of Practice 8 and 9 investigations
Alternative dispute resolution
Appeals and litigation support
VAT and employer compliance disputes
IR35 and status reviews
Contact Information:
Website: www.krestonreeves.com
Twitter: x.com/KrestonReeves
LinkedIn: www.linkedin.com/company/kreston-reeves
Address: 2nd Floor, 168 Shoreditch High Street, London, E1 6RA
Phone: +44 (0)20 7382 1820
Markel Tax
Markel Tax specialise in supporting individuals and businesses through HMRC investigations, with a focus on handling complex and sensitive cases. Their team includes former HMRC professionals, which informs how they approach enquiries and disclosure processes.
They are involved at each stage of an investigation, from initial contact through to resolution, including situations where formal disclosure or dispute resolution is required. Their work often includes managing detailed submissions and preparing clients for meetings with HMRC.
Key Highlights:
Experience across a wide range of HMRC investigations
Team includes former HMRC professionals
Involvement in serious cases including fraud enquiries
Support through full investigation lifecycle
Focus on disclosure and dispute processes
Services:
HMRC compliance enquiries
Code of Practice 8 and 9 investigations
Voluntary disclosures and WDF
Alternative dispute resolution
Employer compliance enquiries
IR35 and status reviews
Contact Information:
Website: uk.markel.com
Twitter: x.com/MarkelUK
LinkedIn: www.linkedin.com/company/markeluk
Address: One Snowhill, Birmingham, B4 6GH
Phone: 0330 822 3555
Conclusion
Choosing a tax investigation advisor in the UK is not always straightforward, and in many cases it only becomes a priority when an enquiry is already underway. Some organisations look for firms with direct HMRC experience, others focus on how the process will be handled day to day, especially when internal teams are already stretched.
What tends to matter in practice is how clearly the firm can guide the situation - from understanding the scope of the enquiry to managing communication and keeping things moving. In more complex cases, experience with disclosures, disputes or tribunal work can also shape the outcome.
This guide was put together to give a clearer view of the firms operating in this space and how their services are structured. It is not a ranking or recommendation, but a way to understand the different approaches and decide what kind of support fits your situation.
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.
Statutory Sick Pay (SSP) is the minimum an employer must pay an employee who is too ill to work. For 2026/27 it is £123.25 a week or 80% of the employee's average weekly earnings, whichever is…
A UTR number is your Unique Taxpayer Reference : a 10-digit number HMRC issues when you register for Self Assessment or set up a limited company. It identifies your tax records for Self Assessment…
A P60 is the end-of-year certificate your employer gives you. It shows your total pay and the income tax and National Insurance deducted from it during the tax year, which runs from 6 April to 5…
Read article
Get in Touch
Ready for Accountants Who Move Your Business Forward?
Tell us what you need. Within one business day, a qualified accountant will be in touch to talk it through and give you a clear, fixed-fee quote — no obligation.
We use essential cookies to run this site, plus Google Analytics and Google Ads to
understand how visitors use it and measure our advertising — only with your consent. See our
Privacy Policy.
