Claire Jeffs > Slaughter and May > London, England > Lawyer Profile

Slaughter and May

Living Wage

Work Department

Global Investigations
Media & Telecoms


Partner; Claire is Co-Chair of the Competition Group globally and works in Slaughter and May’s Brussels and London offices.

Claire has extensive experience of both EU and UK competition law. She has been involved in a large number of high-profile merger cases before the EU and UK competition authorities, as well as coordinating merger approvals worldwide. On the contentious side, she has been involved in many cartel and other behavioural cases, including on appeal to the General Court in Luxembourg.


Joined firm  in 1998. Partner since 2005.


French and Russan (fluent). German (proficient).

Lawyer Rankings

Belgium > Competition: EU and global

Slaughter and May combines an active merger control practice, including high-profile involvement in major global clearances, with a strong record in major antitrust investigations and litigation, notably the Google AdSense case, state aid matters, marketing and consumer issues, and follow-on damages proceedings. The practice is active on behalf of major multinational names, and draws upon expertise from Brussels resident partners as well as London-based members of the Brussels Bar. Key names in the team include Bertrand Louveaux and Claire Jeffs, co-chairs of the competition team, Brussels office head Anna Lyle-Smythe, and Natalie Yeung, who takes the lead on Asia-domiciled matters. Jordan Ellison and Kerry O’Connell are also noted for their strong work on mergers and broad antitrust issues.

London > Corporate and commercial > EU and competition

(Hall of Fame)

Claire JeffsSlaughter and May

Slaughter and May‘s ‘top-class‘ competition group possesses market-leading multijurisdictional capabilities across the full scope of antitrust investigations, merger control cases, subsidy control issues, and consumer law matters. The ‘wonderful‘ global competition co-chair Bertrand Louveaux is reputed for the depth of his practice, advising a mix of blue-chip manufacturers, financial services providers, and tech companies both on transactional matters and before the various regulatory authorities. Fellow global co-chair Claire Jeffs routinely coordinates merger approvals on a global scale, and is also noted for her experience in cartel and other behavioural cases. Philippe Chappatte is a highly experienced EU and UK competition law adviser, with recent highlights including proposed acquisitions in the biotech and health tech sectors. Multinational tech companies and sovereign states alike turn to Isabel Taylor for her expertise in state aid, subsidy control, and competition authority investigations – both at home and abroad. Lisa Wright ‘s recent focus encompasses e-commerce and financial services, while William Turtle has handled matters for the full scope of consumer goods manufacturers – from food and drink to luxury products. Senior counsel Tina Zhuo is also recommended. Jonathan Slade was promoted to partner in May 2022. All named lawyers work between the firm’s London and Brussels offices.