[2][3] Before assuming this role, Bowler was the second permanent secretary at the Cabinet Office from 2020 to 2021 where he led the COVID Taskforce for the British Government.

[10][11] Bowler has also served under Gordon Brown when he was Chancellor of the Exchequer having been appointed as his Principal Private Secretary between 2005 and 2007.

Bowler said the Conservatives' assessment of Labour's tax plans "should not be presented as having been produced by the civil service".

Bowler said the calculation of £38bn of uncosted spending used by the Tories "includes costs beyond those provided by the civil service".

[17] [18] In January 2025, the creation of the National Infrastructure and Service Transformation Authority (NISTA) in April 2025 was confirmed, with Bowler named as the body's principal accounting officer.