Mark O'Conor

Claibourne S. Harrison is a top attorney recognized by Best Lawyers in the practice area(s) of Real Estate Law. Claibourne S., who practices law in London, United Kingdom, has been recognized since 2024. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Claibourne S. is held by other top lawyers in the same geographic and legal practice area.

Mitasha Chandok is an experienced corporate associate in the London office of Gibson, Dunn & Crutcher. She is a member of the firm’s Oil and Gas, Energy and Infrastructure, Power and Renewables, Mergers and Acquisitions, and Private Equity practice groups and the Environmental, Social and Governance (ESG) practice. Mitasha’s experience includes mergers and acquisitions, joint ventures, project development and financing, and corporate advisory work. She routinely advises client...

Fiona Adams is the Managing Shareholder of the London office and the Co-Chair of the Global Corporate Practice. She primarily represents corporate clients, focusing her practice on mergers and acquisitions, and other transactional matters. Her work spans a range of industries, including pharmaceuticals, financial institutions, media and retail. Fiona has broad experience working on large, complex cross-border transactions. Fiona continues to be highly recommended by both of the leading indepe...

Brenda Coleman specialises in all aspects of corporate tax including private equity, fund formation, public and private M&A, restructurings, complex financings and tax disputes. Her experience includes acting for private equity funds, multi-asset managers, LPs, multinational companies, banks, hedge funds, Sovereign wealth funds and various UK Government departments. Brenda is described in Chambers UK 2022 as “extremely capable, very analytical and very thorough.” Clients say &...

Annabel Thomas is a top attorney recognized by Best Lawyers in the practice area(s) of Fraud. Annabel, who practices law in London, United Kingdom, has been recognized since 2025. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Annabel is held by other top lawyers in the same geographic and legal practice area.

Peter Castellon is a top attorney recognized by Best Lawyers in the practice area(s) of Capital Markets Law. Peter, who practices law in London, United Kingdom, has been recognized since 2023. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Peter is held by other top lawyers in the same geographic and legal practice area.

Jason Hambury is a top attorney recognized by Best Lawyers in the practice area(s) of Construction Law and International Arbitration. Jason, who practices law in London, United Kingdom, has been recognized since 2024. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Jason is held by other top lawyers in the same geographic and legal practice area.

James Cox is a partner in the London office of Gibson, Dunn & Crutcher and a member of the firm’s Labour and Employment Practice Group. Mr. Cox has extensive experience in contentious and non-contentious labor and employment matters, with an emphasis on cross-border employment issues, collective labor and industrial disputes, redundancies and workforce restructurings, ARD/TUPE, the employment aspects of public and private mergers and acquisitions and outsourcing arrangements, corpor...

Stephen Pollard is a seasoned litigator with more than 30 years of experience in the full spectrum of business crime and securities enforcement work. During his career, Mr. Pollard has been involved in most of the significant business crime investigations and prosecutions brought by the UK authorities. Mr. Pollard has particular experience in representing senior individuals from public and private companies, including those from the financial services sector. In addition, Mr. Pollard is regul...

Mark Beardsworth is a partner in Cadwalader’s White Collar Defense and Investigations Group, resident in the London office. Mark focuses his practice in the defense of serious fraud and criminal matters and has been involved in prosecutions brought by the Serious Fraud Office, the Financial Services Authority, HM Revenue and Customs, the Financial Reporting Council and the Environment Agency. These cases are often complex, high profile and international in nature. Mark has a special int...