Mark McMahon is a senior associate in Mayer Brown's London office and a member of the Construction & Engineering team and International Arbitration practice. His primary area of work is international arbitration construction disputes.

Mark's experience includes predominantly international disputes involving a wide variety of projects. He has represented clients in complex high-value arbitrations and adjudications.

Mark has considerable experience in complex cross-border matters involving issues of jurisdiction and has worked on cases under the major arbitration rules including ICSID, LCIA, and ICC. He has extensive experience of drafting pleadings and witness statements and has attended numerous hearings both domestically and internationally.

Mark joined Mayer Brown in 2012 as a trainee and spent six months on secondment to Mayer Brown’s New York office during his training contract. Mark spent six months on secondment to Mayer Brown's Hong Kong office in 2017 and was also seconded to Mayer Brown’s Dubai office in 2019.

Spoken Languages

  • English
  • Irish


  • Acting for a leading Spanish contractor in relation to multiple ICC arbitrations concerning the development of solar power plants in North Africa and Sub-Saharan Africa.
  • Working on two separate ICC Arbitrations in connection with major infrastructure projects in Qatar.
  • Working on an ICSID Arbitration for Kuwaiti investors against the Government of Jordan.
  • Advising on a number of ICC arbitrations in connection with the design and construction of a major maritime project in Central America.
  • Working on a multi-million pounds adjudication regarding the interpretation of a major PFI Contract.
  • Advising a leading Gulf contractor on Employer claims and non-payment.
  • Advising a leading UK contractor on issues of sub-contractor non-payment.


Kaplan Law School, LPC

University College London (University of London), LLM

University College Cork, BCL (Hons)


  • England and Wales


  • ICC Young Arbitrators Forum
  • Society of Construction Law