Between 1998 and 2003, Taylor was the Director of the left of centre think tank the Institute for Public Policy Research, and in 2003 the Labour Prime Minister Tony Blair appointed him head of the Number 10 Policy Unit, giving him the task of drawing up the Labour Party's manifesto for the May 2005 general election. Following the re-election of the Labour government he became Chief Adviser on Strategy to the Prime Minister. Taylor was involved in several initiatives to engage the public with the political process, and played a key role in developing the Labour Party's "Big Conversation" discussion forums.