In a speech marking the 75th anniversary of the BBC - delivered less than a month after Labour's leading spin doctors launched a scathing attack on the Radio 4 presenter John Humphrys for giving Harriet Harman, Secretary of State for Social Security, a hard time - Mr Birt sided unequivocally, for once, with his staff, declaring that the corporation's political independence had been hard won and was one of its proudest achievements.
In a pointed passage directed at the Prime Minister's chief press spokesman, Alastair Campbell, and Labour's communications chief Dave Hill, Mr Birt stated: "In modern times savvy politicians seem to have concluded that a full frontal attack - or even a covert threat - is no longer smart politics, for we have won the trust of the people for being above party. Day by day, spin doctors will no doubt continue to seek to influence the BBC's working journalists and to complain when the results are not to their taste. But the context is clear: the political parties may not always like the BBC's journalism but our independence is now acknowledged by all."
This declaration of journalistic independence stands in stark contrast to a controversial speech Mr Birt delivered in Dublin a few years ago, when he expressed sympathy with those who complained that some BBC interviewers were too aggressive.