White Book 2025: Costs & Funding Supplement
We are pleased to report that 4 New Square Chambers’ Roger Mallalieu…
Legal 500
“Theo is incredibly bright, but also very friendly and approachable. He turns things around very quickly and is a joy to work with”
Theo is a versatile barrister with experience who appears in the High Court, Court of Appeal, Supreme Court and various arbitral tribunals. His practice spans all aspects of commercial litigation and arbitration, with an emphasis on high value and high profile disputes. His cases have featured in The Lawyer’s Top 20 Cases for 2021, 2024 and 2025.
Theo is ranked in the legal directories in intellectual property (“detail orientated, personable, and a brilliant advocate“), international arbitration (“Written advocacy is terrific. Well-structured and clear. Very responsive and pragmatic. Pleasure to work with”), sports law (“Highly responsive and engaged. Provides sound advice and has a fantastic understanding of the nuances of sports law“), professional negligence (“One of the most succinct lawyers I have ever worked with in terms of running a case and his drafting ability. He is definitely a star of the future”) and costs and litigation funding (“…lovely to work with and really knows costs and procedure…Costs is a whole new world – experts are needed, of which he is one”).
Theo is particularly praised for his advocacy (“…a slick and accomplished trial advocate, always prepared for every eventuality with an uncanny ability to read the courtroom“; “…calm and unflappable under pressure, with a particular talent for thinking on his feet”), the quality of his written work (“…written advocacy is terrific“) and his manner with clients (“He is a complete pleasure to work with“; “...always attentive and responsive“; “…it is very easy to work with Theo to get the right results for the clients“).
Theo’s commercial practice is wide-ranging, spanning civil fraud, banking and finance, intellectual property, corporate and professional negligence litigation and arbitration. His sports law practice is similarly broad, including regulatory and disciplinary issues, player/agent disputes, IP disputes and commercial litigation in a sports context. He also specialises in costs law, with a particular focus on litigation funding disputes and solicitor/client matters.
His work is frequently international in nature, including international arbitration and English Court litigation involving foreign law.
He has appeared in leading cases across his areas of expertise, including in the Supreme Court and Court of Appeal. His current and recent instructions include appearing for the appellants in the Supreme Court in Iconix v Dream Pairs, which will be a leading case on trade mark infringement; acting for over 1m claimants on costs issues in the NOx Emissions Group Litigation; representing a leading litigation funder in Omni & Therium v Bugsby Property, a £27m dispute about the enforceability of two funding agreements that has reached the High Court on a number of occasions; appearing for the claimant in Skatteforvaltningen v Solo Capital Partners LLP, a £1bn + fraud claim and acting for Liverpool Football Club in LFC v New Balance and Winlink v LFC: two leading sports law cases in the Commercial Court.
Alongside his practice, Theo is one of the editors of the Costs and Litigation Funding supplement to the White Book.
He has also written a book on UK politics (Fighters and Quitters: Great Political Resignations, Biteback 2018) and contributed chapters on Joan of Arc, Henry II and George Canning to The Generals (Hodder and Stoughton, forthcoming), Kings & Queens of England (Hodder and Stoughton, 2023), The Prime Ministers (Hodder and Stoughton, 2022).
Further details about Theo’s practice areas are set out below.
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Theo’s is regularly instructed, led and unled, to act in high value commercial disputes in the Commercial Court, Circuit Commercial Court, Chancery Division and in international and domestic arbitrations.
He has been ranked in Legal500 as a “rising star” for Commercial Litigation, described as “…outstanding. Smart, diligent, hard-working. Absolutely will go as deep into the subject matter as necessary to find the answers and to be prepared…excellent on his feet“.
Theo’s commercial practice encompasses insurance, civil fraud, banking & financial services, intellectual property disputes, sports disputes, litigation funding claims and high-value professional negligence claims, as set out in the sections below.
He has particular experience acting in urgent claims for freezing and proprietary injunctions (domestic and worldwide), including in support of arbitration or foreign seated litigation and at the enforcement stage.
Current and recent cases include:
Theo’s has appeared in several recent leading fraud cases, including as junior counsel in B.V. Nederlandse Van Eiprodukten v Rembrandt Enterprises[2019] EWCA Civ 596, the landmark Court of Appeal authority on the test for inducement in fraudulent misrepresentation (led by Guy Morpuss KC); and
He also has experience of various interlocutory applications in a civil fraud context, including of applications for worldwide freezing orders in support of litigation and arbitration.
Current and recent fraud cases include:
Theo’s intellectual property practice is focused on trade mark law, copyright infringement and passing off. He is instructed in the leading appellate cases in the field, alongside disputes in the Chancery Division and IPEC.
He is ranked as Leading Junior in Legal 500 and Chambers & Partners for Intellectual Property law, who describe him as “detail orientated, personable, and a brilliant advocate” as well as “collaborative and strategic with a firm grip on the legal issues” with “a real awareness of the commercial background and client relationships.”
He is currently instructed as junior counsel to the appellants in Iconix v Dream Pairs, which is to be heard by the Supreme Court in March 2025 and will be the leading authority on the similarity and confusion tests in trade mark law.
In 2023 he appeared in the Court of Appeal in Combe v Dr Wolff [2022] EWCA Civ 1562, which is the leading case on acquiescence in trade mark law.
Other current and recent instructions include:
Theo is building a strong domestic and international arbitration practice, with a range of claims under a variety of institutional rules, including ICC, SIAC, LCIA, Swiss Rules and FA Rule K.
He is ranked as a Leading Junior in international arbitration by the Legal 500. His written advocacy is praised as “terrific“, “well structured and clear” and he is described by clients as “very responsive and pragmatic” and a “pleasure to work with“.
He has particular experience:
He also has expertise on the principles of awarding costs of arbitration, having acted in Martin v Harris, a High Court appeal on costs under the Arbitration Act 1994.
Featured arbitration cases:
Theo is ranked as a Leading Junior for costs litigation in Chambers & Partners and the Legal 500 and is described as:
“Theo has a sound knowledge of subject matters and his written work and advocacy skills are exceptional.”
“Theo is incredibly bright, but also very friendly and approachable. He turns things around very quickly and is a joy to work with.”
He recently appeared in Therium Litigation Funding v Bugsby Property LLC and Omni Bridgeway v Bugsby Property LLC, the first post-PACCAR cases in the Commercial Court concerning the enforceability of litigation funding agreements.
His practice covers the whole spectrum of costs law, including:
He is also regularly instructed:
His current and recent instructions include:
Theo has a wealth of experience in professional liability claims, having advised and acted in claims involving tax advisors, solicitors, auditors, accountants, surveyors, construction project managers and engineers.
He is ranked as a leading junior in professional negligence by Legal 500: “Theo is a slick and accomplished trial advocate, always prepared for every eventuality with an uncanny ability to read the court room. He is destined for greatness.”
In his professional liability practice, he acts for both claimants and defendants in cases in the county courts and the High Court.
Featured professional liability cases:
Theo is very experienced in advising and acting in professional liability claims against legal professionals. He acts for both Claimants and Defendants.
He has experience in the full range of solicitor and barrister liability claims, including lost litigation, under settlement, Limitation Act claims, domestic and international conveyancing negligence and claims arising out of personal injury litigation.
He has also acted in claims against solicitors relating to non-contentious transactions that have failed, such as business sales and wills claims.
Current and recent instructions include:
Theo has extensive experience of claims involving accountants and auditors, which has included the following:
Current and recent cases include:
Theo has experience acting in claims involving auditors, brokers, actuaries, IFAs and tax advisors.
He has a strong background in investment advice work, having worked for three years on behalf of the Financial Conduct Authority as a ‘skilled person’ under s.166 FSMA, reviewing compensation claims made by SMEs that had been miss-sold Interest Rate Hedging Products.
He also has experience of claims made against mortgage brokers and financial advisors for negligently recommending Interest Only mortgages.
Current and recent cases include:
Theo has experience in broker’s negligence claims – an area he is well placed to advise due to his practice in Insurance Law. His experience includes acting and advising on:
Theo has experience of claims involving a broad range of surveys (from regular residential property surveys to damp and asbestos surveys). His experience covers a spread of issues, from subsidence to damp, advice on value and the quantum of rectification works.
He is also experiences in claims against Property Managers, including:
Theo advises on multi-million pound claims against tax advisors, solicitors and accountants arising out of failed tax mitigation schemes, including employee benefit schemes and Enterprise Investment Scheme investments.
He has worked on these cases as sole counsel and as part of a wider team.
Current and recent cases include:
Theo specialises in sports-related commercial litigation and regulatory work.
He is recognised as a Leading Junior in Sports Law in Chambers & Partners and the Legal 500, in which he is described as “….no longer a rookie and is becoming a seasoned pro. A team player of fierce intellect.” and “….phenomenally bright and pays astounding attention to details. He is a very good team player and a skilful advocate.”
He has appeared for Liverpool Football Club in two of the largest football-related claims in the English courts and worked on disputes relating to the ownership of Sheffield United FC and Rangers FC. He acts on behalf of and against other Premier League football clubs and sporting institutions, advising on contractual issues between clubs and players, sponsorship disputes, negotiations with governing bodies, litigation with suppliers, and intellectual property issues.
He has also advised and acted on matters concerning Formula 1, golf, cricket, boxing, athletics and horse racing.
Featured sports cases:
In his advisory practice, Theo has provided assistance to several major sporting venues and institutions on the contractual problems caused by the Covid-19 pandemic, including advising:
Theo is a regular contributor to:
Theo has experience in insurance litigation, having acted for and against insurers. Recently, he has advised and acted in a number of business interruption matters arising out of the Covid-19 pandemic.
He has acted in cases covering the full range of liability insurance, including legal expenses insurance, D&O, employers, public, product and professional indemnity. He has also appeared in a number of insurance fraud and misrepresentation matters, including the pursuit of fraudulent claimants.
He has experience in coverage disputes between insurers relating to run-off insurance and double insurance scenarios.
Theo studied Modern History at Brasenose College, Oxford, where he was an academic exhibitioner. He then achieved a Distinction in the Graduate Diploma in Law at City University, London, placing second in his year group.
Theo has been awarded Hardwicke, Lord Haldane, Lord Denning, Lord Wolfson scholarships by Lincoln’s Inn. In 2017 the Inns of Court awarded Theo a Pegasus Scholarship to undertake a two-month fellowship in the United States to study comparative law.
Theo is a member of COMBAR, the British Association of Sport & Law, the PNBA and the Financial Services Law Association.
Outside of law, Theo’s first book, Fighters and Quitters: Great Political Resignations was published by Biteback in January 2018 (Hardback) and February 2019 (Paperback).
He wrote the chapter on George Canning in The Prime Ministers: Three Hundred Years of Political Leadership (Hodder & Stoughton, November 2020) and the chapter on Henry II in Kings & Queens (Hodder & Stoughton, September 2023).
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