Central Policy Unit
He was head of the government's think tank, the Central Policy Unit, for a decade from 2002. In this role, he famously under-predicted attendance on the 1 July 2003 protest march at '30,000', when in fact more than 500,000 joined to reject the planned introduction of legislation to enact Article 23 of the Basic Law, along with other grievances, ultimately leading to the resignation of Chief Executive Tung Chee Hwa.