The search begins for a new DG at the BBC
Tony Hall has been an effective director general of the BBC, while probably having a tougher job than any of his predecessors.
His leadership of Britain's most important cultural organisation can be split into three chapters.
He joined at a time of enormous crisis and difficulty, following the revelations over Jimmy Savile, the disgraceful mistreatment of Lord McAlpine, and the disastrous, short reign of his predecessor George Entwistle. (Tim Davie had been interim).
That first chapter was a case of steadying the ship, and crisis management, where he is widely thought to have performed well.
The second chapter was securing a new Royal Charter and governance structure at the BBC. This included a painful negotiation with the government which some critics argue the BBC should have been tougher in, while of course those at the BBC argued they were very happy with the new deal.
The third chapter has been navigating unprecedented technological disruption. On this, he has done much more than he is generally credited for. Personalisation with sign-in for BBC iPlayer; extending BBC iPlayer viewing to 12 months (after much attrition with Ofcom); overseeing the launch of BBC Sounds; merging BBC Studios and Worldwide to make the BBC a stronger player in IP; and a major partnership with Discovery.
All of these have been attempts to keep the BBC in the new global race, and they have come while the BBC has received new levels of scrutiny over pay, following the demand from government that they publish many more salaries.
Director general of the BBC is one of the most privileged, but also one of the most relentless and tough jobs in Britain - and it gets tougher every day, because of the technological context.
His successor will need to combine world-class political, commercial, editorial and managerial talent, while coming under a relentless barrage of criticism from all fronts.
The question of who gets it will depend on where the BBC Board and its chairman, Sir David Clementi, want to place their emphasis. Someone with commercial nous, or someone who can charm Boris Johnson and Dominic Cummings? Someone with a track record at managing talent - or someone who can make a brave, correct call on a Panorama investigation?
The perfect candidate will be able to do all this - and therefore doesn't exist