James is an international lawyer, policy adviser and entrepreneur, a barrister called in 1987. He has appeared in leading cases in environment, trade and human rights including the arrest of General Pinochet, Hinkley Point, and the Shrimp/Turtle case at the World Trade Organisation.

James has negotiated international agreements such as Kyoto Protocol and the Framework Convention on Climate Change, represented several developing nations in dispute settlements, advised the European Commssion on regulating Greenhouse gas emissions, and was a member of the UK Prime Minister's Business Advisory Group.

 James founded Climate Change Capital a specialist investment firm in 2003, is currently Chairman of Overseas Development Institute, a leading research based think tank on development, Chairman of Agrica, a sustainable agriculture business, a member of General Electric's Ecomagination Board, a Trustee of the Green Building Council, a Trustee of CDP an organisation which works with shareholders to disclose corporate data on emissions, water use and forest depletion, and a Sustainable Development Commisioner for London.