Boutique tax firm Joseph Hage Aaronson & Bremen LLP is respected in the market for its ability to handle large tax disputes and group litigation in the First-tier Tribunal, Upper Tribunal, High Court, Court of Appeal, UK Supreme Court and CJEU. The team is spearheaded by Graham Aaronson KC, who is relied on by a full spectrum of taxpayers, from industrial corporations and financial service businesses to entrepreneurs and HNWIs; and Michael Anderson, who has established experience in tax litigation at all levels of the UK’s Tax Tribunals, domestic courts and European Court. Iain MacWhannell enjoys a market leading presence in cases involving HMRC’s investigative powers, tax fraud, tax evasion and tax abuse. Daniel Margolin KC is well versed in HMRC litigation, and Helen McGhee has strong credentials in COP9 investigations. Simon Whitehead retired from the firm in January 2025.
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Profile

Profile

Work Department
Contentious Tax, Commercial & Chancery Litigation, Investigations.
Position

Iain was called to the Bar in 2006 and his practice focuses on contentious tax, allegations of fraud/avoidance/abuse, and investigations. He has litigated several of the leading cases on HMRC investigative powers, VAT fraud, and the Knowledge/Means of Knowledge tests.

Iain manages a wide variety of work for an international client base, ranging from UHNWIs to PLCs and owner-managed businesses to trusts and funds.  He is often sought out by other legal and professional advisors for a second opinion and to help ‘unlock’ long-running or complex disputes.

Career

Before pupillage, Iain worked for HMRC Solicitor’s Office in both Excise litigation and VAT litigation. He has acted as counsel both for and against HMRC in a variety of disputes in the Tax Tribunal, Upper Tax Tribunal, High Court (Admin, ChD and Comm), Court of Appeal (Civil), House of Lords and UK Supreme Court.  He became a partner at JHA in 2021 and prior to that had been a tenant at a leading set of Chambers and a Dispute Resolution Partner at a City law firm.

Memberships
Bar of England & Wales.

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Key clients

  • British American Tobacco Plc Universal Music Evonik FCE Bank Plc ‘The VAT Umbrella Appeals’ “Post-Prudential” Closure Notice Appeals and Closure Notice Applications (PPCN) Group Litigation The Evonik group of companies (Evonik UK Holdings Limited & Others) Impact Contracting Solutions Ducas Ltd Enix Ltd FL Capital Ltd The Kittel Class Action AXA Insurance UK Plc AXA Insurance Plc Redevco Properties UK Limited Dandara Group

Work highlights

Acting as the lead solicitors in the Franked Investment Income (“FII”) GLO.