Heywood joined HM Treasury, and became the Private Secretary to Chancellor Norman Lamont at the age of 30, staying in this role under Chancellors Kenneth Clarke and Gordon Brown before being promoted to be the Principal Private Secretary to Prime Minister Tony Blair in 1999.
Heywood joined HM Treasury in 1992 and became the Principal Private Secretary to Chancellor Norman Lamont at the age of 30, having to help facilitate the fallout from Black Wednesday after less than a month in the job. Heywood remained in this role throughout the 1990s under Chancellors Kenneth Clarke and Gordon Brown before being promoted to be the Principal Private Secretary to Prime Minister Tony Blair in 1999.