Craig Oliver, the BBC executive who will become David Cameron's new Director of Communications, had accepted another job at the Corporation shortly before leaving for Downing Street.
Mr Oliver had agreed to take on the role of reviewing all the BBC's television news output in addition to his job at the World Service. The position had been offered to him personally by the Director-General, Mark Thompson, and was seen internally as a sign that he was being lined up to take control of the entire BBC news operation.
However, on the day his new job was announced, Mr Oliver took many colleagues by surprise with the news that he was leaving the BBC.
"It came completely out of the blue," said one member of staff. "We heard about his first new job a few days ago and then he went and left."
Senior BBC executives are known to be concerned by Mr Oliver's switch from "poacher to gamekeeper". Far from believing that it will give them an "in" with Downing Street, they are worried that Mr Oliver will feel the need to prove himself to his new political masters by complaining more about the BBC's coverage.
Producers and editors are already familiar with calls from Downing Street complaining about the accuracy – and sometimes the tone or the prominence – of the stories they run. They believe these calls may well become more frequent.
Mr Oliver replaces Andy Coulson, the former News of the World editor who resigned two weeks ago as more allegations emerged of phone hacking by the paper's staff.
The BBC has already made clear that, because of the nature of his new job, Mr Oliver will not be required to serve out any notice period. He could start at Downing Street next week.Reuse content