Giles has worked in human-computer interaction for sixteen years at Euro RSCG Circle, British Aerospace and Institute of Physics Publishing. He worked on some of the world's first commercial websites for Institute of Physics Publishing in 1994. He has conducted usability studies in every continent except Antarctica - from as far afield as Russia, China, Australia, and the US to nearby France, Ireland and of course the UK. His clients include Peugeot, Marriott and Nokia.
Giles was President of the UK Usability Professionals Association from 2003 - 2007. He writes on usability for Revolution magazine and is a frequent speaker at conferences around the world. He sits on the editorial board for IST45 - the forthcoming accessibility standard from the British Standards Institute and was an editorial board member for PAS 78, the BSI's accessibility guidance for web site owners.