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

Slaughter and May

Living Wage

Work Department



Partner. Claire works in the firm’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 world-wide. On the contentious side she has been involved in many cartel and other behavioural cases, including on appeal to the General Court in Luxembourg.


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


University of Cambridge, University of Brussels

Lawyer Rankings

London > Corporate and commercial > EU and competition

Within: Leading individuals -

Claire Jeffs

Slaughter and May

Slaughter and May’s competition group provides full-service competition law advice on high-profile merger control cases, contentious and regulatory issues, and state aid matters. The London team works seamlessly with the firm’s sole continental European office in Brussels, advising on high-profile matters including Vodafone’s proposed £18.4bn acquisition of Liberty Global’s telecoms business in Germany, the Czech Republic, Hungary and Romania. The group is also representing clients in a number of Phase II merger cases before both the CMA and the European Commission; among multiple examples, one noteworthy highlight is advising Tata Steel on its proposed joint venture with thyssenkrupp, aiming at the creation of a leading European steel enterprise. Another stable source of work for the team comes in the form of  instructions from clients in the consumer protection space. Practice head Philippe Chappatte leads a team advising two parties in the CMA consumer law investigation into accommodation booking sites, while Bertrand Louveaux is leading on handling competition law aspects of client GlaxoSmithKline’s divestment of Horlicks and other consumer healthcare nutrition brands to Unilever. Claire Jeffs has been leading a team assisting Google with the European Commission’s Article 102 investigation into its AdSense for Search advertising services. Isabel Taylor has particular expertise in state aid law. Special adviser Jackie Holland stands out for her significant experience in the public and private sectors.