John has appeared in and argued most of the seriously important commercial tax cases of the last forty years. Starting with the basis of Schedule E expenditure in Taylor v Provan  1 AC 194 (HL) and Edwards v Clinch  AC 845 (HL) and Schedule D in Ransom v Higgs  1 WCR 1594 (CA) and Taylor v Good  1 WLR 556 (CA), and moving on to his forte – serious financial transactions for large corporate bodies: banking and accounting – Willingale v International Commercial Bank  1 AC 834 (HL), VAT characterisation – British Railways Board v Customs  1 WLR 588 (CA) and National Coal Board v Customs  STC 863 (QBD), banking currency transaction – Pattison v Marine Midland  1 AC 362 (HL), oil field abandonment costs – R.T.Z. Oil and Gas v Ellis  1 WLR 1442 (ChD); judicial review, validity of subordinate legislation and restitution – the twoWoolwich cases  1 WLR 1400 (HL) and  AC 70 (HL), which fundamentally changed the law on restitution, and National and Provincial Building Society v UK  ECHR 87 (ECHR); fiscal recharacterisation – Ensign Tankers v Stokes  1 AC 655 (HL); building societies and banks – Halifax etc.  STC (SCD) 251 (SpC); UK legislation in breach of the EU Treaty – Metallgesellschaft Ch 620,  ECR 1-1727 (ECJ); “share buy backs” – Sema Group Pension Fund v IRC  STC 95 (CA); and international repo financing – HMRC v Bank of Ireland Britain Holdings  STC 398 (CA).
As well as practising in the UK he has advised upon tax in many foreign countries particularly Hong Kong, Malaysia, India and Singapore and for over thirty five years has argued innumerable cases in Hong Kong, many of which also have a bearing on UK tax law (e.g. CIR v HIT Finance Ltd and Hong Kong International Terminals  10 HKCFAR 717 and Beautiland Co Ltd v CIR  STC 467 (PC)). He acts as an arbitrator and also as an expert witness in UK and foreign litigation, most recently in a significant investment treaty arbitration in The Hague on retrospective legislation [ Cairn Energy PLC and Cairn UK Holdings v Republic of India PCA Case No 2016-7 Decision 21 December 2020 ] .
- HMRC v Payne and others  UKUT 90 (UT) – employee benefits for cars/vans
- Lomas and others v HMRC  EWCA Civ 2124 (CA) – liability for witholding tax on £1.2bn of interest payments – before both the HC and the CA.
- Greene King v HMRC  EWCA Civ 782 (CA) – corporate loan relationships, accounting and tax;
- HMRC v FCE Bank  STC 14 (CA) – treaty non-discrimination;
- Land Securities v HMRC  UKUT 124 – corporate funding and capital gains;
- Scottish Widows plc v HMRC  All ER 379 (SC) – insurance taxation;
- HMRC v First Nationwide  EWCA Civ 278 (CA) – foreign dividends;
- HMRC v Lansdowne Partners Limited Partnership  STC 544 – hedge fund partner rebates;
- HMRC v DCC Holdings  STC 326 (SC) – repo financing.
- MA, LLM Cantab (Law, 1st, 2.1) Q.C. (1982), FRSA (2001),
- Treasurer of the Senate of the Inns of Court and Bar Council (1985-86)
- Harmsworth Scholar and Bencher (1992) of the Middle Temple (Chairman of its Finance and Scholarship Appeal Committees for many years).