Joseph Hage Aaronson LLP

JHA's contentious tax team is led by the renowned Graham Aaronson KC, who has developed a trusted relationship with HMRC (appointed by them to chair the GAAR Interim Advisory Panel), and with the UK Government (appointed by the Treasury to lead the GAAR study, and subsequently by the Prime Minister, David Cameron, in relation to the "Panama Papers" allegations about his family).

Others in the team include Michael Anderson, Paul Farmer, Simon Whitehead, Iain MacWhannell, Richard Doran, Ray McCann, Helen McGhee, Daniel Margolin KC, Lynnette Bober, Steve Bousher, Joe Irwin, Megan Durnford, Grace Webster, John Hayton, Julia Glukhikh and Thomas Hemming. They are supported by in-house barristers, solicitors, pupils, and accountants, combining the best qualities of the bar and a law firm to deliver a cohesive approach to advising and representing clients throughout all stages of a dispute. In some of the most complex and sensitive private client cases we bring in the expertise of Emma Chamberlain OBE, the renowned private client counsel with whom the firm has a close and long-standing relationship.

JHA, being the only law firm in the market which specialises in contentious tax, we remain the firm of choice for the most sensitive, important and high value tax disputes. JHA’s lawyers have experience across all the domestic courts and tribunal system, from the First-tier Tribunal to the Supreme Court. We also represent UK and overseas clients in references to the Court of Justice of the European Union, and in overseas courts in high-value, complex tax disputes.

As is well known, JHA have also been the lead and test-case solicitors in almost all corporation tax Group Litigation Orders (GLOs), which bring together High Court claims made by more than 50 multinational corporations. These are ground-breaking claims that challenge various discriminatory elements of UK tax legislation.

We have particular expertise in relation to COP8 and COP9 HMRC enquiries (and in some cases criminal investigations), where we work proactively with HMRC to achieve the best possible outcome for our clients, while paying the closest attention to preserving their privacy and maintaining confidentiality.

In more recent years, JHA has also built a strong reputation for our tax fraud/abuse and tax investigations work, including our role as lead and test case solicitors in the largest VAT Group Litigation that has ever taken place in the Tax Tribunal.

Our team has acted in many of the most sensitive and highest value disputes of recent years, including those involving novel issues in Transfer Pricing, Diverted Profits Tax, and the compatibility of domestic tax rules with EU state aid rules.

Many of the cases JHA are currently litigating will be at the forefront of the development of law in the post-Brexit environment, especially those disputes that involve the interaction of the Retained EU Law (Revocation and Reform) Act 2023. We continue to run a series of major challenges to tax legislation before the Court of Appeal and Supreme Court as well as acting in proceedings in the European Court and we representing clients in multiple tax-focused civil and criminal investigations.

Where it is essential to do so we will carry a dispute through to litigation to achieve the result which we and the client consider to be the correct application of the tax law to the particular facts. But our preference wherever possible is to seek to persuade HMRC (or the relevant overseas tax authority) that the client’s filing position is correct, or to reach a settlement on the best possible terms.

Notable practitioners

■ Graham Aaronson KC

■ Daniel Margolin KC

■ Michael Anderson

■ Simon Whitehead

■ Iain MacWhannell

■ Paul Farmer

■ Helen McGhee

■ Richard Doran

■ Steve Bousher

■ Emma Chamberlain OBE

■ Ray McCann

■ Lynnette Bober

■ Joe Irwin

■ Megan Durnford

■ Grace Webster

■ John Hayton

■ Julia Glukhikh

■ Thomas Hemming