Christopher is a consultant with the London law firm Collyer Bristow LLP. After studying law at Cambridge University and comparative law at the Vrije Universiteit, Amsterdam and lecturing in law at Sheffield University, he was admitted as a solicitor in 1978. He then practised in London for over twenty years, specialising in intellectual property litigation.

In 1999 he was appointed a member of the Boards of Appeal at the EPO, becoming a member of the Enlarged Board in 2005 and chairman of a biotechnology technical board in 2010. He was chairman or member in hundreds of EPO appeal cases and, since 2007, many petitions for review. He was one of the draftsmen of the current Rules of Procedure of the Boards of Appeal. He has lectured regularly in patent law since 2001 and from 2007 onwards was also involved in judicial training for both new members of the Boards of Appeal and judges from European national courts.

He retired from the Boards of Appeal in April 2014 and re-joined his previous firm where he now advises on all aspects of EPO proceedings and procedure, patent and other IP litigation in England and the co-ordination of parallel litigation. He also acts as an arbitrator in IP disputes and continues to be actively involved in teaching and training in patent law and procedure.