Trained as a forensic auditor and economist, John has worked in many countries around the world, including a period of working in offshore financial services with Touche Ross & Co. For 11 years he was economic adviser to the government of the British Channel Island of Jersey.
In 2003 he became what the Guardian has described as “the unlikely figurehead of a worldwide campaign against tax avoidance.” His research on offshore finance has been widely published in books and academic journals, and John has taken part in many films, television documentaries and radio programmes.