OVERVIEW

Joanna Christoforou has extensive experience on EU and UK competition law, including competition litigation and complex multi-party investigations in the EU and UK.

Expertise

Joanna has had a leading role in significant competition litigation and investigation matters before the European Commission and European courts; the UK Competition and Markets Authority (CMA), Competition Appeal Tribunal (CAT), Court of Appeal, and Supreme Court; and antitrust agencies in other jurisdictions. She acts for clients in complex, high-value cartel or abuse of dominance court proceedings and investigations, damages actions, competition disputes, dawn raids and director disqualification proceedings.

Joanna represented a leading national retailer in the leading case against Visa in the interchange fee litigation in the English courts, with successful appeals to the Court of Appeal and Supreme Court and represented a leading pharmaceutical company in its challenge to the CMA’s search warrants in a first-of-its-kind litigation. She has also represented clients in the successful appeals against the CMA’s decisions in each of Hydrocortisone and Prochlorperazine, the appeal against the CMA’s decision in Liothyronine and appeals against director disqualification proceedings.

She was seconded to the Competition and Cooperation Panel (then Monitor), where she advised on the introduction of a competition law regime to the UK National Health Service (NHS).

Joanna also maintains an active pro bono practice and has assisted Amicus, a not-for-profit organisation, with providing representation to individuals facing the death penalty in the United States.

Clients

Joanna works across a broad range of industries, including life sciences, technology, retail, grocery, ecommerce, financial services, commodities, and healthcare. Her clients describe her as “highly accomplished and effective” and praise her for her “excellent support” and for showing “a real sense of being on your side, even when conveying tough messages.”

EDUCATION

Cambridge University, Downing College, LL.M.
Cambridge Judge Business School, Postgraduate Diploma, Management Studies
Cambridge University, Downing College, B.A. and M.A. (Cantab), Law

BAR ADMISSIONS

Solicitor, England and Wales
Brussels

AFFILIATIONS

Member, Competition Law Association
Member, Law Society Competition Section

WHAT OTHERS SAY

Joanna has worked on competition cases or as part of teams which came highly commended at the Lawyer Awards in 2021 and 2022; by Global Competition Review in 2018 and by Law360 between 2017 and 2021 - to mention but a few.

Legal 500

Legal 500 UK ranks Joanna as a Leading Individual for Competition Litigation in the 2025 edition and has done so since 2020. They have recommended her as a key lawyer every year since 2016 for EU and Competition Law.

She is noted for representing “a broad range of clients across the life sciences and technology industries in matters concerning abuse of dominance investigations and appeals before the Court of Appeal and the Supreme Court” and for her “expertise in big-ticket cartel and abuse of dominance investigations, and consequent court proceedings.” Her clients have commented that Joanna and her then team were “extremely skilled and responsive and bring a real depth of experience in this complex and challenging area.” Clients also note that she is “always on hand during a transaction to offer top class insights which allow for clear and fully informed decision making.” Her clients describe her as “highly accomplished and effective” and praise her for her “excellent support” and for showing “a real sense of being on your side, even when conveying tough messages.”

Pro Bono Recognition list

In 2024, Joanna was recognised as part of the newly launched List, published annually, which celebrates solicitors and barristers who have dedicated 25 or more hours of legal assistance in the previous calendar year. The list is under the patronage of The Lady Chief Justice of England & Wales and is supported by The Law Society, Bar Council and all major pro bono legal organisations.

Experience

Antitrust/Competition

At Hausfeld, Joanna is part of the legal team:

Filing a representative collective action with the CAT on behalf of the Consumers’ Association (known as Which?) against Qualcomm on behalf of a class of around 29 million UK consumers alleging that Qualcomm abuses its dominance in the markets for smartphone chipsets and standard essential patents, the result of which is that Qualcomm is able to overcharge smartphone manufacturers like Apple and Samsung for its technology. Damages are estimated to be over £480 million.
The opt-out collective action filed with the CAT on behalf of an estimated 19.5 million eligible UK users of smartphones and tablets running on Google’s Android operating system relating to excessive and unlawful charges on purchase in the Google Play store. The claim alleges that Google unfairly restricts consumers from accessing potential competition from other app distributors, by requiring smartphone manufacturers to pre-install a bundle of Google’s proprietary apps and services including the Google Play Store as well as imposing other contractual and technical restrictions.

Prior to Hausfeld, Joanna:

Acted for a leading national retailer in its claim against Visa for damages at the UK High Court and Court of Appeal and in its 2020 landmark victory at the UK Supreme Court, which upheld the Court of Appeal's 2018 judgment in favour of the retailer’s claim that Visa’s UK multilateral interchange fee was an unlawful restriction of competition under UK and EU law; prior to the relevant proceedings there had been no English or EU ruling that Visa’s interchange fee was a restriction of competition
Acted for a leading pharmaceutical company at the High Court and Court of Appeal in the first-ever challenges to the CMA’s search and seize warrants brought under Section 28 of the Competition Act 1998
Acted for a leading pharmaceutical company in its successful appeal in the CAT against the CMA’s infringement decision relative to market exclusion and pay-for-delay in relation to Hydrocortisone, having also acted in the administrative proceedings relative to the same
Acted for a leading pharmaceutical company in its appeal in the CAT against the CMA’s infringement decision alleging abuse of dominance by charging unfair and excessive prices in relation to Liothyronine, having also acted in the administrative proceedings relative to the same
Acted for a leading pharmaceutical company in its successful appeal in the CAT against the CMA’s infringement decision relative to market sharing and market exclusion in relation to Prochlorperazine, having also acted in the administrative proceedings relative to the same
Successfully advised clients against director disqualification proceedings pursued by the CMA
Acted in numerous investigations into suspected complex cartels, anticompetitive agreements and abuse of dominance pursued by the European and UK agencies, including relative to Nitrofurantoin and other medicines, credit default swaps, Libor and Euribor, Forex, with a successful outcome for the clients in many of these
Acted for a Fortune 500 company in its internal investigation into suspected market sharing and price fixing and its application for immunity or leniency to enforcement agencies, including the European Commission
Advised a global tobacco manufacturer in its successful appeal to the CAT in 2011 against the OFT’s decision and record fine in respect of alleged anticompetitive retail pricing practices; the infringement decision was annulled by the CAT
Served as a Blue Book stagiaire at the European Commission’s Directorate General for Competition

Pro Bono

In 2024, Joanna was recognised as part of the newly launched Pro Bono Recognition List, published annually, which celebrates solicitors and barristers who have dedicated 25 or more hours of pro bono legal assistance in the previous calendar year.

She has worked on the following cases:

For Amicus, a not-for-profit organisation which represents individuals facing the death penalty in the United States, Joanna has led teams supporting US counsel representing a number of individuals on death row, including in a case in which prosecutors subsequently dropped the death penalty
Co-led a team assisting Reprieve, a human rights not-for-profit organisation, in relation to a pro bono study on the appeals system in a jurisdiction