When HMRC opens an enquiry or issues a tax assessment, the response a business gives in the first weeks often determines how the dispute unfolds across the months or years that follow. Ferraz & Whitmore advises international businesses and investors on the full arc of UK tax disputes – from the initial HMRC review through the First-tier Tribunal, Upper Tribunal, Court of Appeal and, where necessary, the Supreme Court or treaty-based mutual agreement procedures. Our role is to protect your legal position, manage procedural risk and align the UK dispute with any parallel proceedings in other jurisdictions.
When Businesses Need Specialist Tax Dispute Counsel in the UK
Tax disputes rarely begin dramatically. An HMRC enquiry may open quietly under the self-assessment regime or as a formal investigation into a corporate tax return. The moment a business receives a notice of enquiry, a request for information or a preliminary closure notice, professional legal involvement becomes important – not because the position is necessarily wrong, but because procedural steps taken at that early stage are difficult to reverse.
International businesses face additional complexity. Transfer pricing adjustments, disputes over the application of the substantial shareholding exemption, challenges to Patent Box or R&D relief claims, and HMRC scrutiny of group relief arrangements all involve technical arguments that may also trigger exposure in other jurisdictions. A UK litigation strategy therefore cannot be designed in isolation from the wider group structure.
If your business is facing an open HMRC enquiry, a discovery assessment or a penalty notice, we are available to discuss the position at an early stage. Please contact us at info@ferrazwhitmore.com or visit our contacts page.
The UK Tax Dispute Pathway: From HMRC to the Supreme Court
The UK has a structured, multi-stage dispute resolution framework. Understanding where a matter sits within that framework – and what options remain open – is essential before any decision is made about whether to appeal, negotiate or litigate.
HMRC Enquiry and Closure Notice
HMRC may open an enquiry into a return within defined windows. For most corporate taxpayers the enquiry process concludes with a closure notice. Where the taxpayer disagrees with HMRC's conclusions, the formal response is either to request an internal statutory review or to notify the First-tier Tribunal directly. This notification must be made within 30 days of the decision under challenge (TMA 1970 s.31A). Missing this deadline extinguishes the right of appeal unless HMRC or the Tribunal grants an extension, which is not guaranteed.
Discovery Assessments and Time Limits
HMRC has the power to raise a discovery assessment where it believes tax has been underpaid and the matter was not otherwise protected by a valid return. The time limits within which HMRC may raise such assessments vary by the nature of the behaviour alleged:
- 4 years from the end of the relevant period – the ordinary time limit (TMA 1970; FA 1998 Sch 18).
- 6 years – where HMRC alleges careless behaviour by the taxpayer or its agents.
- 20 years – where HMRC alleges deliberate behaviour.
The characterisation of behaviour is therefore not merely a question of degree; it determines whether an assessment is in time at all. Challenging HMRC's characterisation is one of the most consequential – and under-utilised – lines of defence available to a taxpayer.
Statutory Review and First-tier Tribunal
A taxpayer who disagrees with an HMRC decision may request an internal statutory review before triggering formal litigation. The review is conducted by an HMRC officer not previously involved in the matter. Where the review does not resolve the dispute, or where the taxpayer elects to bypass it, the next step is an appeal to the First-tier Tribunal (Tax Chamber). The Tribunal is an independent judicial body and its proceedings are governed by established procedural rules. Evidence, disclosure and witness requirements must be managed carefully from the outset.
Upper Tribunal, Court of Appeal and Supreme Court
Appeals from the First-tier Tribunal on points of law proceed to the Upper Tribunal. Further appeals on points of law of general public importance may reach the Court of Appeal and ultimately the Supreme Court. At these higher levels, proceedings are subject to the Civil Procedure Rules (CPR) and the standards of appellate advocacy differ significantly from Tribunal proceedings. Our litigation team has experience at multiple levels of the UK court hierarchy; further detail is available on our UK litigation and arbitration practice page.
Advance Certainty: Clearances and Advance Pricing Agreements
Not all tax risk needs to be managed through dispute. Where a transaction or structure is under consideration, HMRC offers mechanisms designed to provide certainty before a commitment is made. Non-statutory clearances allow a taxpayer to seek HMRC's view on the application of specific provisions to a proposed arrangement. Advance pricing agreements (APAs) allow multinational groups to agree the transfer pricing methodology to be applied to controlled transactions for a defined period, reducing the risk of future adjustment by HMRC or a foreign authority.
The decision to seek advance certainty involves its own strategic considerations: the information disclosed to HMRC in the clearance process may have implications beyond the specific question asked. Businesses considering this route should obtain legal advice before initiating contact with HMRC. Our UK tax structuring practice works alongside our dispute team to assess when a proactive HMRC engagement is the right approach.
Cross-Border Disputes: MAP and Treaty Arbitration
Where a UK tax adjustment creates or threatens to create double taxation – for example, where HMRC makes a transfer pricing adjustment affecting the profit allocation between a UK entity and a related party in another jurisdiction – treaty-based mechanisms become relevant alongside domestic litigation.
Most of the UK's double tax treaties include a mutual agreement procedure (MAP) under which the competent authorities of both states seek to resolve the inconsistency. For transfer pricing disputes within the European Union, the EU Arbitration Convention 90/436/EEC provides an additional route. Separately, the Tax Dispute Resolution Mechanisms Directive (EU) 2017/1852 provides a framework for mandatory binding arbitration in cases involving EU member states.
MAP proceedings operate on a government-to-government basis and do not suspend domestic limitation periods or appeal rights automatically. A business facing a cross-border adjustment must therefore manage the domestic and international timelines simultaneously. Failure to protect the domestic appeal in time can leave the taxpayer with no enforceable position even if the MAP produces a favourable outcome.
If you are dealing with a cross-border tax dispute that touches the UK, please write to us at info@ferrazwhitmore.com or use our contacts page to arrange an initial discussion. We regularly coordinate with counsel in other jurisdictions to present a consistent position across multiple proceedings.
Regulatory Intersections: FCA, OFSI and Companies House
In certain situations, a tax dispute is not the only regulatory matter in play. Businesses operating in regulated sectors may find that an HMRC enquiry runs in parallel with scrutiny by the FCA or with obligations arising under OFSI financial sanctions rules. Similarly, discrepancies in the information held at Companies House may become relevant where HMRC examines the ownership or control of a UK entity. Our cross-practice teams are structured to handle these overlapping exposures without creating additional risk through siloed advice.
Typical Pitfalls in UK Tax Disputes
Based on the matters our teams handle, the following errors recur most frequently in UK tax disputes involving international businesses:
- Missing the 30-day appeal window. Once the deadline passes, the right of appeal is lost unless an extension is granted. Extensions are discretionary and are not routinely given.
- Treating the statutory review as a delay rather than a strategic step. The review process, if engaged properly, can produce a revised decision and narrow the issues before Tribunal proceedings begin.
- Failing to coordinate UK litigation with MAP requests. Domestic proceedings and treaty claims interact in ways that can close off options if not managed together.
- Conceding the characterisation of behaviour. The difference between an ordinary, careless or deliberate assessment affects both the time limit available to HMRC and the range of penalties that may follow.
- Disclosing documents to HMRC without legal review. Information provided voluntarily during an enquiry can be used in any subsequent litigation and may also be exchanged with foreign authorities under automatic information exchange regimes.
- Underestimating Tribunal procedure. The First-tier Tribunal (Tax Chamber) has its own procedural rules and case management expectations. Treating it as a less formal forum than the High Court is a common mistake in complex cases.
A Practical Self-Assessment: Is Your Position Protected?
Businesses reviewing their exposure to a current or potential UK tax dispute may find the following questions useful in identifying where gaps exist:
- Have all appeal and review deadlines been identified and diarised from the date of the HMRC decision?
- Is the dispute purely domestic, or does it involve cross-border pricing, treaty residence or foreign entity characterisation?
- Has the relevant behaviour been characterised by HMRC, and has that characterisation been reviewed by an adviser independent of the original return preparer?
- Are there parallel regulatory considerations – FCA, OFSI, Companies House – that could be affected by documents or positions taken in the tax dispute?
- Is an advance pricing agreement or non-statutory clearance a viable alternative to litigation for the underlying arrangement?
Our detailed procedural guide to challenging an HMRC assessment is available at Tax Audit: Challenging an Assessment in the United Kingdom.
How Ferraz & Whitmore Approaches UK Tax Disputes
We act as coordinating counsel for international groups whose UK tax disputes form part of a wider cross-border exposure. Our role is to bring together the domestic legal arguments, the treaty claims and the group-level considerations into a single coherent strategy. We do not promise any particular outcome; we focus on protecting the legal position at each procedural stage and ensuring that options are not closed off by delay or procedural error.
Our work in this area sits at the intersection of tax, corporate law and cross-border litigation. We maintain working relationships with specialists in transfer pricing economics, forensic accounting and regulatory compliance, and we engage them where the facts of a matter require it.
To discuss a UK tax audit, assessment or dispute, please contact us at info@ferrazwhitmore.com or visit our contacts page. Early legal involvement typically preserves more options than intervention at a later stage.
Disclaimer: This publication is provided for informational purposes only and does not constitute legal advice. The information herein should not be relied upon as a substitute for professional legal counsel tailored to your specific circumstances. Ferraz & Whitmore assumes no liability for actions taken or not taken based on the contents of this material. For advice regarding your particular situation, please contact info@ferrazwhitmore.com.