Slaughter and May (London)

Claire Jeffs

Slaughter and May (London)
Lawyer (Partner)

Claire was educated at Cambridge and Brussels universities and works in Slaughter and May’s Brussels and London offices. 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 Vodafone on its acquisition of parts of Liberty Global; Shire on its takeover by Takeda; and Google in relation to the European Commission’s antitrust investigation into allegations that certain of its business practices in the search and advertising sectors violate European competition rules. Claire is fluent in French and Russian and has good German.

Linked authors

University College London
ESSEC Business School (Cergy)
University of Oxford
General Court of the European Union (Luxembourg)
UK Competition Appeal Tribunal (London)
Oxera (Oxford)
United Kingdom’s Competition Authority - CMA (London)
Skadden, Arps, Slate, Meagher & Flom (Brussels)


557 Bulletin

Claire Jeffs, Nele Dhondt Dominance & Monopolization Research Program: An overview of EU and national case law


The number of jurisdictions across the globe with a competition law regime has increased dramatically over the last couple of decades and many of these regimes include rules on abuse of dominance. Competition agencies in jurisdictions with long-established antitrust regimes (such as the EU, UK and US) have used these rules to impose significant fines on firms with a dominant market position. Enforcement has also picked up in jurisdictions with more recent regimes, such as China. This is a foreword to a database of commentary on decisional practice and case law in the area of abuse of dominance covering over 35 sectors, including pharmaceuticals, transport, utilities, distribution/retail, information technology and online platforms. The focus of the database is on Europe but the database also includes commentary on cases and developments in other jurisdictions such as Brazil, Canada, China, India, Japan, Mexico, Russia, South Africa and the US. Figure 1 below contains a complete list of the sectors and jurisdictions covered. This foreword discusses legal developments up until and including 9 March 2020.

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