JUNIOR PROFILE

Thomas Sebastian

UK Bar 2026

Monckton Chambers

Ranked in 2 practice areas

Public International Law

London (Bar)

8 years ranked

Competition Law

London (Bar)

8 years ranked

Chambers Review

Provided by Chambers

UK Bar

Public International Law - London (Bar)

Band 2

Individual Editorial

Thomas Sebastian is highly regarded for his investment treaty and WTO work. He has acted in treaty disputes involving Cuba, Colombia, Thailand, India and South Africa, and has also advised the UK government on Brexit-related international law issues.

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Competition Law - London (Bar)

Band 3

Individual Editorial

Thomas Sebastian is well known for his handling of major competition cases for clients from the technology sector. He defends clients in investigations into possible abuse of dominance and cartels, and also has experience acting for claimants in collective proceedings.

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Strengths

Provided by Chambers

He is a straight shooter. He is very direct, honest and thorough.
Public International LawUK Bar
He's extremely intelligent and unfailingly calm under pressure. He's a real diplomat, excellent at liaising with clients and adept at plotting a path through difficult legal challenges.
Competition LawUK Bar
Thomas is very, very good on the detail. For complex matters he's really excellent - he doesn't fluff over any details and gets right down to the nitty gritty.
Competition LawUK Bar