Stephen is a Senior Lecturer in Law at King’s College London, where he teaches EU tax law, the law of business taxation and company law. He previously taught at the Universities of Birmingham and Oxford and has held visiting positions at the Max Planck Institute for Tax Law and Public Finance (as a guest researcher in 2021 and as a Hugh Ault Fellow in 2019) and at the University of New South Wales. He holds degrees in law from University College Cork, University College London and the University of Oxford. He is also a CTA (Fellow).

He published his doctorate with Hart Publishing (HMRC Advice and the Public (2020)) and has published in leading academic journals (British Tax Review, Fiscal Studies, Law Quarterly Review, Modern Law Review, Public Law), in various edited collections and specialist tax publications (Bulletin for International Taxation, Intertax, Tax Notes).

He is a member of the Tax Law Review Committee of the Institute for Fiscal Studies, on the editorial boards of the British Tax Review (book review editor) and the Journal of Tax Administration (managing editor (law)) and a member of HMRC’s Guidance Strategy Forum.

My research primarily concerns the legal aspects of tax administration, which can be broken down into three relatively discrete areas:

1. The study of public law through the lens of tax administration. My doctoral research investigated HMRC soft law – the importance of such soft law, the problems that are experienced in practice in relation to it and changes that should be brought about. This research led to an article in the Journal of Social Welfare and Family Law, which undertakes an assessment of the role that the Ombudsman can play in overseeing HMRC soft law, my monograph which looks more broadly at the assistance provided by tax authorities (Tax Authority Advice and the Public (Hart 2020)) and an article in King’s Law Journal (2021) assessing the role of soft law during the COVID-19 pandemic. How administrative discretion is used by tax authorities in managing the tax system more generally was analysed in chapters in Essays in Honour of Judith Freedman (Hart 2020) and Studies in the History of Tax Law (Hart 2017).
2. The relationship between tax and State aid. Several of my articles consider how tax administration can engage the EU State aid rules and to that end make propositions about the appropriate interaction between them. ‘The power to get it wrong’ in the Law Quarterly Review (2021), argues that the State aid rules should accommodate misapplications by domestic tax authorities, whilst ‘The constitutional implications of an EU arm’s length principle’ in European Taxation argues against the idea that EU law autonomously requires arm’s length treatment between associated enterprises. My paper ‘OMC, intelligent accountability and monitoring national tax authorities’ in the Modern Law Review (2022), argues that there ought to be a supranational means of holding tax authorities to account over their failure to properly apply tax rules in the EU and that ‘intelligent accountability’ should be adopted, which can be embedded in open method of coordination initiatives.
3. The role of taxation in society. My work has considered whether the tax system can positively respond to societal problems: through expanding the tax base (Mumford, Spangenberg and I published a lengthy research article in the Columbia Journal of European Law in 2019 which considers means of using EU law to develop sustainable taxation; Loutzenhiser, Hughson and I published an article in Fiscal Studies in 2021 on issues around valuation in wealth taxes); and implementing fiscal policy in an emergency (2023 Accounting and Business Research article). In 2022, Lawton and I published original research on the health of tax teaching in UK higher education (British Tax Review, 2022).

1. The study of public law through the lens of tax administration:

• Tax Authority Advice and The Public (Hart 2020)
• ‘Drawing the boundaries of HMRC’s discretion’ in Rita de la Feria and Glen Loutzenhiser (eds), Essays in Honour of Judith Freedman (Hart 2020)
• ‘Public law in the tax tribunals and the case for reform’ [2018] British Tax Review 94
• ‘Recent developments in tax law: vires revisited’ [2016] 2 Public Law 190

2. The relationship between tax administration and State aid:

• ‘Fiat v Commission: a misconceived approach’ (2023) Modern Law Review
• 'The OMC, intelligent accountability and the monitoring of national tax authorities' (2022) 85(5) Modern Law Review 1109
• 'The power to get it wrong’ (2021) 137(2) Law Quarterly Review 280
• ‘The constitutional implications of an EU arm’s length principle’ (2020) 60(2/3) European Taxation 70
• w/ R. Mason ‘State Aid: The General Court Decision in Apple’ (2020) 99(10) Tax Notes International 1317/ (2020) 168(10) Tax Notes Federal 1791

3. The role of taxation in society:

• ‘Tax systems - adaptability and resilience during a global pandemic’ (2023) 53(5) Accounting and Business Research 561
• w/A. Lawton, ‘Another check of the temperature of tax teaching in the UK’ [2022] 2 British Tax Review 202
• w/ H. Hughson and G. Loutzenhiser, ‘Valuation for the purposes of a wealth tax’ (2021) 42(3/4) Fiscal Studies 615
• w/ U. Spangenberg and A. Mumford, ‘Moving beyond the narrow lens of taxation: The Sustainable Development Goals as an Opportunity for Fair and Sustainable Taxation’ (2019) 26(1) Columbia Journal of European Law 36