Katie Mahoney

Senior Associate | London (City)

Katie Mahoney Photo

Katie acts for a variety of clients, predominantly employers, on a wide array of employment law issues. Katie deals with both contentious and non-contentious matters, including unfair dismissal, constructive dismissal, redundancy, discrimination, post termination restrictions and day-to-day workplace issues.

Katie is a senior associate with significant experience advising on all aspects of contentious and non-contentious employment law. She trained at and subsequently qualified into the employment law team at the international city law firm, Norton Rose Fulbright LLP, and joined the employment law team at Doyle Clayton in 2013.

Recognised as a leading employment lawyer by the legal directories (listed as a “Key Lawyer” in The Legal 500 and both a “Notable Practitioner” and an “Associate to Watch” in Chambers & Partners), comments and feedback include - 

  • “a senior associate that has made fast progress through the ranks and must now be on the edge of partnership. Excellent with clients, a punchy and highly effective communicator, very mature understanding of court processes, fantastic work ethic, negotiates exceptionally well and gets brilliant results.”  The Legal 500
  • “a stand out star. Impressive but approachable, she is a hard worker, who knows what she is doing and is particularly effective. A delight to work with.”  The Legal 500
  • “Katie Mahoney has a wonderful manner with clients and is utterly assiduous.”  The Legal 500
  • “very well recognised by practitioners in this field as being involved in lots of high profile employee competition cases. She is someone with extensive knowledge of this sector, with extremely high standards and a true fighter for her clients.”  The Legal 500
  • “particularly collaborative, responsive and has very strong relationships with her clients.”  The Legal 500
  • “I was immensely impressed by Katie’s dedication and hard work, and her ability to always think a step ahead. She was alive to the unique legal and strategic issues that arise in these types of cases, and demonstrated a considered and confident approach to dealing with issues as they arose”  The Legal 500
  • “developing great expertise in the employee competition area, particularly team moves. She is always positive and a delight to work with.”  The Legal 500
  • “assists senior executives with a range contentious employment issues. She is recognised for her knowledge of team moves and post-termination restrictions”  Chambers and Partners
  • "She has a superb approach and attitude to matters and is a total pleasure to deal with.”  Chambers and Partners
  • "She's really good; she does lots of employee competition work and is really on top of that area. She definitely stands out."  Chambers and Partners
  • “an up and coming senior associate with an incredible memory, strong work ethic and excellent client relationship skills"  The Legal 500


Bringing a commercial and practical approach to employment issues faced by clients, Katie supports both employers and employees on all issues arising in the workplace. Areas she regularly advises on include redundancies and business restructurings, executive contract negotiations/exit arrangements, day to day workplace issues (including disciplinary and grievances, bonus issues and disputes (particularly obtaining/resisting injunctions), settlement agreements, post termination restrictions and protection of confidential information) and projects and transactional work (covering the employment aspects of mergers, acquisitions, business transfers and advice on outsourcings).

Having worked on a number of high value and complex injunctions and speedy trials, Katie is known for her particular expertise in High Court litigation, particularly in relation to team moves, the enforcement of restrictive covenants and misuse and protection of confidential information. Over the years she has been involved with a number of the team's notable successes including Bluefin v Global Risk Partners, OCS v Dadi and Alesco and others v The Ardonagh Group and others. Additionally, Katie is experienced at dealing with arbitrations (especially those brought in the LCIA) and has recently worked on an arbitration in respect of an alleged team move.

Katie also advises LLPs on partnership matters and is experienced in the issues that may affect their members. Recent work includes a high-profile LLP dispute in which one of the leading asset managers brought proceedings in the High Court for a declaration that an exercise of an option under an LLP Agreement was not valid (F&C Alternative Investments (Holdings) Ltd v Barthelemy & Culligan).

Katie supports clients across multiple business sectors including financial services, insurance (brokers and underwriters), telecommunications, media, tech and online businesses. Corporate clients range from well-known global brands and internationally listed organisations to entrepreneurial businesses and start-ups. Katie also regularly acts for employees. 


Recently reported cases include - 

Employee Competition (including disputes relating to post termination restrictions)

Bluefin Insurance v UK Credit Insurance and others [2014] – Claim brought by a leading insurance broker in the High Court (initially with an application for a springboard injunction) in relation to the removal of confidential information, an unlawful team move and breach of post termination restrictions.
Bluefin Insurance v Global Risk Partners and others [2016] – Claim brought by a leading insurance broker in the High Court (initially with an application for a springboard injunction) in relation to the removal of confidential information, an unlawful team move and breach of post termination restrictions.

OCS v Dadi and others [2017] – Claim brought in the High Court (initially with an application for a springboard injunction) in relation to removal of confidential information and which also involved imprisonment for one of the defendants who was in contempt of court for breach of the interim injunction made by the court in respect of the confidential information order.

Alesco v Ardonagh and others [2019] – Damages claim brought by a leading insurance broker in the High Court in respect of claims of an alleged unlawful team move and an alleged unlawful means conspiracy.
Information Builders (UK) Limited v Peter Walker [2019] – Claim brought in the High Court in respect of alleged misuse of confidential information.

Investec v Muzinich and others [2019] – Claim brought by a leading bank against an asset management company and five employees in the High Court (initially with an injunction application for springboard relief) in relation to an alleged unlawful team move and an unlawful means conspiracy. 


Employment Appeal Tribunal

Aslam v Travelex UK Limited [2015] UKEAT/0028/15/LA - The leading authority on when an employment tribunal can lawfully dismiss a claim for non-payment of tribunal fees.


Certification Office

Professor Pollock v British Medical Association [2019] D/1/20-21 – Defending a case brought in the Certification Office in respect of an application made by Professor Pollock, under section 108A(1) of the Trade Union Labour Relations Act 1992 alleging that the British Medical Association had breached the rules of the union. 


LLP and Partnership

F&C Alternative Investments (Holdings) Ltd v Barthelemy & Culligan [2011] EWHC 1731 (Ch) – Claim brought in the High Court in respect of, inter alia, fiduciary duties and claims for unfair prejudice (section 994 of the Companies Act) in the context of an LLP. 


Katie regularly provides bespoke training for clients and speaks at employment law seminars and webinars. She is also a member of the Employment Lawyers’ Association and sits as a member of the Employment Appeal Tribunal Users Group Committee. Katie also writes regularly on various areas of employment law and has been featured in the Employment Lawyers’ Association monthly briefing as well as other HR publications. She is frequently quoted in the The Huffington Post and the BBC on contemporary employment law matters in the news.



Experience and qualifications -

  • Qualified in February 2012
  • Specialist in Employment Law since 2012


Professional memberships -

  • Employment Lawyers Association


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