Justin Coombs

"Justin is a first rate economic expert. We instructed him on a complex antitrust damages claim: he is a first rate and highly experienced economist, and has real gravitas as an expert witness." - Lexology Index 2024

Justin Coombs is an Executive Vice President with Compass Lexecon, co-head of the London office and head of the Hong Kong and Singapore offices.

Justin has more than three decades’ experience as an applied economist specialising in competition policy and economic regulation.

Justin has advised clients in cases before the UK Competition and Markets Authority, the European Commission and numerous national competition authorities. He has provided expert reports to the UK Competition Appeal Tribunal, the High Court of England and Wales, the European Union General Court, the Irish High Court and the Singapore Competition Appeal Board. He has given evidence at numerous Competition and Markets Authority and European Commission hearings as well as before Parliamentary select committees.

Previously, Justin was a Director at the UK Office of Fair Trading where he was in charge of the enforcement of UK and EU antitrust law in the UK service sector. During his career at the OFT, he advised on and led a wide range of competition policy cases and drafted many of the OFT’s guidelines on UK competition law, including its guidelines on market definition and abuse of dominance. Justin has also worked at Ofgem, the UK energy regulator, where he was the Director responsible for regulating the gas and electricity transmission networks in Great Britain.

Justin is listed by Lexology as a thought leader in competition economics. He teaches part of the King’s College London Postgraduate Diploma/Masters course in Economics for Competition Law.

"Great competition economic analysis, commercial awareness, application of highly complex principles in an understandable and effective manner." - Lexology Index 2025

"Commercial and pragmatic. Highly technically capable. Calm under pressure and supportive and collaborative working with external counsel." - Lexology Index 2025

"Justin is highly skilled as a competition economist, very client-friendly and provides consistent excellence in his service." - Lexology Index 2025

"Fantastic to work with, very efficient economist." - Lexology Index 2024

"Justin is first rate, and helps me (as a Partner) look good with my clients." - Lexology Index 2024

"Understands the importance of positioning economic arguments and evidence within the applicable legal framework (and potential tensions between the two). Experienced, flexible and easy to work with, collaborative with our whole team and with the client." - Lexology Index 2025

"Knowledgeable and inspires confidence but also asks questions to understand and contribute to wider context and strategy and ensure that economic workstreams add maximum value." - Lexology Index 2025

"Excellent analytical and client relationship skills." - Lexology Index 2024

"Calm, thoughtful and knowledgeable." - Lexology Index 2025

"Good understanding of the legal strategy. Always very responsive. Always nice to work with." - Lexology Index 2024

"He provided high quality economic assessment." - Lexology Index 2024