Jeffrey Sullivan KC

Ranked in 4 Practice Areas

Band 1

International Arbitration

4 Years Ranked

Band 2

Energy & Natural Resources: Disputes

3 Years Ranked

Band 3

Arbitration (International)

Global Market Leaders

5 Years Ranked

Band 4

Arbitration (International)

Europe-wide

2 Years Ranked

Ranked in Guides

UK 2026

Europe 2025

Chambers Review

Provided by Chambers

Chambers Global Guide

International Arbitration - UK

Band 1

Individual Editorial

Jeffrey Sullivan KC is co-chair of Debevoise's arbitration group in Europe. He is particularly known for his expert handling of claims brought under the ECT, which forms part of his extensive investor-state arbitration practice. He demonstrates strength across the energy and infrastructure sectors.

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Energy & Natural Resources: Disputes - UK

Band 2

Individual Editorial

Jeffrey Sullivan KC of Debevoise & Plimpston is a respected energy disputes lawyer with strong experience of handling claims in both the oil and gas and renewables sectors. He is highly adept at assisting with Energy Charter Treaty claims and the annulment of intra-EU investment treaties.

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Arbitration (International) - Global Market Leaders

Band 3

Individual Editorial

Jeffrey Sullivan KC is based in London and is widely recognised for his ability to lead arbitrations across a plethora of sectors and industries, most notably in energy and infrastructure. He also has a wealth of experience advising high profile international clients before major arbitral tribunals under ICSID, UNCITRAL and LCIA rules.

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Arbitration (International) - Europe-wide

Band 4

Individual Editorial

Jeffrey Sullivan KC is well regarded for his broad practice undertaking complex commercial and investor-state arbitrations. He has expertise in a range of matters related to energy and infrastructure.

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Strengths

Provided by Chambers

Jeff is always available, delivers straightforward practical advice and is great at handling clients.

International Arbitration respondent
Chambers Global Guide

Jeffrey provides excellent support.

International Arbitration respondent
Chambers Global Guide

Jefferey is extremely clear and sees any issues straight away.

International Arbitration respondent
Chambers Global Guide

Jeffrey is an excellent operator with extensive experience, sensible judgement and measured advice.

International Arbitration respondent
Chambers Global Guide

Jeffrey has an excellent technical skill set.

International Arbitration respondent
Chambers Global Guide

Jeffrey is super impressive and a great guy.

Energy & Natural Resources: Disputes respondent
Chambers Global Guide

Jeffrey Sullivan is an excellent advocate and partner when managing matters. He runs cases excellently and comes up with fantastic advocacy points.

Energy & Natural Resources: Disputes respondent
Chambers Global Guide

Jeffrey delivers straight forward practical advice and has great client-handling skills.

Arbitration (International) respondent
Chambers Global Guide

Jeffrey is very succinct in his advice and is very knowledgeable on the subject matter.

Arbitration (International) respondent
Chambers Global Guide

Jeffrey is a great leader, pragmatic and conveys complex issues in a simple way. He also has great oral and written communication skills.