Augustine Thomas O’Donnell, Baron O’Donnell, (born 1 October 1952) is a former British senior civil servant and economist, who between 2005 and 2011 (under three Prime Ministers) served as the Cabinet Secretary, the highest official in the British Civil Service.
O’Donnell announced after the 2010 General Election that he would step down within that Parliament and did so at the end of 2011. His post was then split into three positions: he was succeeded as Cabinet Secretary by Sir Jeremy Heywood, as Head of the Home Civil Service by Sir Bob Kerslake (in a part-time role), and as Permanent Secretary in the Cabinet Office by Ian Watmore. Whilst Cabinet Secretary, O’Donnell was regularly referred to within the Civil Service, and subsequently in the popular press, as GOD; this was mainly because of his initials. In 2012, O’Donnell joined Frontier Economics as a Senior Advisor.