Lord John Thomas practiced at the Commercial Bar in London from 1972. He was appointed to the High Court of England and Wales in 1996. He was a Presiding Judge of the Wales and Chester Circuit 1998 - 2001 and Judge in Charge of the Commercial Court 2002-3. In 2003, he was appointed to the Court of Appeal and was Lord Chief Justice of England and Wales (2013-2017). He is President of the Qatar International Court and an arbitrator and takes part in the business of the House of Lords.  He is Chair of the Steering Committee of the Standing International Forum of Commercial Courts, Chair of the London Financial Markets Law Committee, President of the London Shipping Law Centre, Chancellor of Aberystwyth University and a Fellow of several Universities. He was a Founder of the European Law Institute in 2011, its First Vice-President 2109-2023 and President of the European Network of the Councils of the Judiciary 2008-2010.