The 2012 Olympics in London are, according to some, being threatened by the chaos at the Department for Culture, Media and Sport.
Dame Sue Street, permanent secretary at the department, left amid accusations that she clashed with Tessa Jowell, culture secretary.
Dame Sue was questioned by Sir Gus O'Donnell, cabinet secretary, as to whether Ms Jowell had breached the ministerial code by failing to declare a $600K gift received by Mr Mills from an Italian source in 2000.
The Cabinet Office said that it was "appalled by the suggestion that Sue Street left for any other reason than her desire to pursue other goals".
Hugo Swire, shadow culture secretary, accused the culture department of trying to "bury this news" by announcing it on its website on a Friday afternoon during the Easter recess.
"This is just the latest proof of the chaos and disarray in Tessa Jowell's department. Criticism of licensing, confusion over gambling, delays over Wembley, let alone the problems caused by Ms Jowell's personal position - all point to the chaos enveloping her department.
With her top civil servant jumping ship, very real questions are now raised [about] the ability of Tessa Jowell's department to [stay] focused on delivering the 2012 Olympics."