Stewarts is a market-leading, award-winning Tax Disputes practice, acting for corporates, institutions and individuals in high-value disputes with HMRC and tax-driven commercial litigation.

We advise on disputes across all areas of tax, including income tax, capital gains tax, VAT, corporation tax and environmental taxes. Our work also extends to tax-related commercial claims involving negligent advice, warranty disputes, misrepresentation, fraud and failed transactions.

Clients instruct us for our ability to combine deep tax-technical expertise with substantial disputes experience, delivering strategically clear advice in situations involving significant financial exposure, regulatory scrutiny and reputational risk.

A distinctive unified disputes capability

What sets us apart is our ability to advise on both HMRC disputes and tax-driven commercial litigation.

Many tax disputes do not exist in isolation. HMRC investigations can expose wider issues involving professional advisers, counterparties, transactions or investment structures. Equally, commercial disputes can trigger tax consequences or regulatory scrutiny.

Our integrated expertise enables us to develop a unified strategy across both the HMRC and civil dimensions of a dispute, ensuring consistency, avoiding fragmentation and strengthening our clients’ position throughout.

Expertise in high-value HMRC disputes

We advise on complex HMRC enquiries, investigations and litigation, from initial engagement through to negotiated settlement or proceedings before the Tax Tribunal and courts.

Our experience includes major disputes involving direct and indirect taxes, COP8 and COP9 investigations, large-scale enquiries, portfolio settlements and matters involving substantial tax exposure. We are currently acting on disputes involving well over £850 million of tax in issue and have a proven track record of achieving successful outcomes in some of the market’s most significant tax controversies.

Technical expertise that informs strategy

All of our lawyers are specialists in tax disputes, the team combines experience gained at leading law firms, HMRC Solicitor’s Office, the Tax Bar and Big Four firms. This breadth of experience allows us to analyse disputes from technical, strategic and commercial perspectives, providing clients with practical advice grounded in a deep understanding of how tax disputes are resolved in practice.

Our approach combines rigorous technical analysis with commercial judgement, enabling clients to make informed decisions at every stage of a dispute.

Strategic negotiation backed by litigation strength

Tax disputes are rarely resolved through technical arguments alone.

Successful outcomes depend on how issues are evidenced, presented and negotiated. We engage with HMRC with clarity and authority, shaping discussions to achieve our clients’ objectives while carefully managing wider commercial, governance and reputational considerations.

This approach has delivered exceptional results for clients, including securing the full withdrawal of an eight-figure capital gains tax assessment after reshaping the legal and evidential position, and achieving a substantial reduction in a nine-figure tax assessment together with full penalty relief through strategic negotiation.

Where a favourable outcome cannot be achieved through negotiation, we litigate confidently before the Tax Tribunal and Civil Courts, drawing on deep trial experience and a strong record in complex, high-value disputes.

Acting in crisis-driven situations

Tax disputes often emerge unexpectedly. Whether triggered by an HMRC intervention, whistleblower allegations, internal reviews or the discovery of previously unidentified liabilities, clients frequently need urgent advice and strategic direction.

We move quickly to establish the facts, assess exposure and stabilise the situation. Our experience enables us to conduct focused investigations, identify priorities and create a clear path forward during periods of uncertainty and pressure.

Aligning stakeholders and managing complexity

Significant tax disputes often involve a range of stakeholders, including boards, parent companies, shareholders, auditors, insurers and professional advisers.

We help clients navigate this complexity by aligning key stakeholders around a coordinated strategy and ensuring clear decision-making throughout the dispute.

This broader perspective allows us to manage not only the legal issues but also the operational, governance and commercial implications of a tax controversy.

Managing reputational risk

Tax disputes can create significant reputational challenges, particularly where allegations of fraud, avoidance, negligence or governance failures arise.

We manage confidentiality, communications and narrative control alongside the legal strategy, ensuring sensitive issues are handled carefully and strategically.

Our approach helps clients protect their reputation while maintaining focus on achieving the best possible outcome.

Delivering closure and certainty

Our objective is not simply to reduce liabilities or win individual disputes. We focus on securing outcomes that achieve our clients’ financial objectives while also delivering clarity, certainty and a stable basis for future dealings with HMRC and, where relevant, commercial counterparties.

By resolving disputes in a way that reflects both legal and commercial realities, we help clients move forward with confidence.

Our expertise is recognised by Chambers, Legal 500, International Tax Review and Spear’s, with multiple partners individually recognised as leaders in the field. The team was also named Tolley’s Tax Award Best Tax Disputes Team, reflecting the strength of our practice and the results we achieve for clients.