Michael Grade leaves at an important time for the BBC
BBC chairman Michael Grade is to leave the corporation and move to its rival ITV.
What are the implications for the BBC, ITV and Michael Grade himself?
Q. What effect will Michael Grade's exit have on the BBC?
Michael Grade can no longer be a powerful advocate for the BBC while he is in limbo between the BBC and ITV, says BBC business editor Robert Peston.
The corporation has still not negotiated the licence fee settlement which is due to come into effect next year, and Michael Grade has been leading the charge for there to be an increase in the fee above the rate of inflation.
That demand has been bitterly resisted by the chancellor Gordon Brown who thinks the fee should be cut in real terms, and ITV does not want the BBC to have a generous settlement.
ITV has got a new boss who has television in his blood, and although he will have his work cut out rebuilding ITV audiences and advertising, Michael Grade has left behind a BBC whose future has suddenly become a little more uncertain.
Q. What will this mean for Michael Grade - and ITV?
ITV has just rebuffed a takeover bid from Richard Branson and NTL, and seen almost 18% of its shares bought by the satellite company BSkyB.
Michael Grade was due to take over as chairman of the new BBC Trust which will replace the Board of Governors on 1 January. Instead he will be joining its biggest rival as executive chairman.
As a former chief executive of Channel 4, director of BBC Television, and ITV programme director his appointment will cheer ITV and its shareholders who have seen audiences and advertising tumble.
His uncle was the ITV mogul Lew Grade, and he will relish the task of trying to improve the network's fortunes, says BBC media correspondent Torin Douglas.
Q. What has the BBC said about the news of Michael Grade's departure?
Michael Grade leaves a big hole at the BBC as it moves into a new charter and system of governance over which he led the negotiations, says Torin Douglas.
In a statement the BBC said the news had come as a surprise but for the last two and a half years Michael Grade had been a great chairman who, along with the director general Mark Thompson, had achieved a successful charter settlement for the BBC. It said it wished him well.
Q. What were reasons behind Michael Grade being brought in at the BBC?
Michael Grade is the man who was appointed by government to sort out the BBC and to put it back on a even keel, says BBC News correspondent Nick Higham.
His predecessor Gavyn Davies resigned in the wake of the Hutton inquiry, and the chief executive at the time, director general Greg Dyke, also resigned.
Michael Grade was the man who was going to come in and sort everything out and see the BBC into the future.
Now he leaves with that job essentially half done, says Nick Higham.