Mair Williams is an associate in the Litigation & Trial Department of Latham & Watkins and is based in the London office.

Ms. Williams’ practice focuses on white collar defense. She has considerable trial experience having started her career as a criminal barrister in chambers, as well as experience in investigations, representing companies and individuals before regulators and prosecuting bodies, and developing compliance policies and practices for international clients.

In addition to her white collar work, Ms. Williams has experience in all manner of complex commercial litigation and has represented clients at every stage from initial pleadings through to trial and appeal.

Ms. Williams qualified as a barrister (England & Wales) in 2010 and passed the California bar in 2016.

Ms. Williams’ recent experience includes:

  • Conducting an international internal investigation on behalf of an international pharmaceutical company following allegations or bribery
  • Representing an individual in a large scale money laundering investigation
  • Advising an international bank on its duty of confidentiality in respect of requests for UK-based documents by foreign criminal enforcement agencies
  • Representing an international manufacturing company in a bribery investigation conducted by a development bank
  • Advising client on requests for information about the Investigatory Powers Act
  • Representing multiple individuals in a spoofing investigation conducted by the US Department of Justice
  • Representing multiple defendants in a claim for breach of fiduciary duties and loss of opportunity in the English High Court
  • Advising a UK-listed company on interactions with the Financial Conduct Authority investigating insider trading
  • Conducting an internal investigation on behalf of a private pension scheme following allegations made by a whistleblower
  • Representing a director in an investigation by the Financial Reporting Council in to discrepancies with annual accounts of a FTSE 250 company*
  • Representing a publically listed investment firm in investigations by the Financial Conduct Authority and Serious Fraud Office*
  • Internal investigation in investment management firm*
  • Advising international companies on the applicability of the Modern Slavery Act 2015 and drafting appropriate compliance policies and procedures*
  • Conducting transaction due diligence and contractual analysis on compliance, corruption, supply chain, sanctions, and bribery issues for international clients *
  • Successfully defending a real estate company at trial in litigation based on breach of contract in the High Court*
  • Acting for an American airline in English civil cartel litigation *
  • Internal investigation of a financial services firm following a leak of confidential information to the media*
  • Advising UK-based and international clients on compliance with the prevention of facilitation of tax evasion offence introduced by the Criminal Finances Act 2017*
  • Representing an international pharmaceutical company under monitorship in the US*
  • Prosecuting on behalf of the Crown Prosecution Service, Department of Work and Pensions, HMRC and Local Authorities*
  • Acting for individuals prosecuted by the Crown Prosecution Service in the Magistrates’ and Crown Court*
  • Acting for requested persons in extradition proceedings*
  • Defending individuals in prosecutions by the Serious Fraud Office*
  • Acting as disclosure counsel for HMRC in high-profile prosecution of an individual*
  • Defending individuals prosecuted by the Crown Prosecution Service*

*Matter completed prior to joining Latham

Ms. Williams has an active pro bono practice focused on representing individuals in the criminal justice system, as well as providing legal advice to charities and NGOs.

Bar Qualification

  • California
  • England and Wales (Barrister)


  • LL.M., BPP Law School, 2012
  • Bar Vocational Course, BPP Law School, 2010
  • Graduate Diploma in Law, BPP Law School, 2009
  • M.A. in History & Political Science, Trinity College, Dublin, 2008

Languages Spoken

  • English