Claire Jeffs

Claire Jeffs
Slaughter and May
One Bunhill Row
+44 20 7090 4031
+44 20 7090 5000

Biography: Competition

Claire was educated at Cambridge and Brussels universities and is resident in London.

She has been involved in a large number of high-profile merger cases before the UK and EU 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.

Highlights include advising: Motorola on the European Commission’s investigation into its enforcement of standard essential patents; INEOS on its styrenics joint venture with BASF; Unilever on its settlement of the European Commission's investigation into the consumer detergents sector; and Google in relation to the European Commission's ongoing antitrust investigation into allegations that certain of its business practices in the search and advertising sectors violate European competition rules.

She has been named in Global Competition Review’s "40 under 40", The Lawyer’s Hot 100 list and Management Today’s "35 under 35" list of high-flying young businesswomen. Claire was recently named “Best in Competition/Antitrust” at the by Euromoney Legal Media Group's Europe Women in Business Law Awards 2013.

Claire is also listed as a leading individual in the competition/European law section of the 2013 editions of Chambers Europe and Chambers Global; in the competition/foreign experts” section of Chambers Global (2013); and in the EU competition section of IFLR1000 (2013).

Claire is fluent in French and Russian, and has good German. 

This biography is an extract from The International Who's Who of Competition Lawyers which can be purchased from our Bookstore.

This profile is taken from Who's Who Legal. For more legal practitioner and firm profiles visit

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