Mr Birt also confirmed the new strategy of broadening the appeal of the BBC's programmes to a wider audience, as set out on Tuesday by Liz Forgan, managing director of radio, and Alan Yentob, controller of BBC1.
Answering criticism that only a minority of listeners wanted all-news radio, he said surveys showed that between 16 and 25 per cent of the population do want it, evenly spread across social groups and regions.
'Some commentators have suggested that if only a quarter of the people want a news service, that must mean a majority of people don't want one. But that really is completely to misunderstand what the BBC is about. Not one of our radio networks would poll a majority of the population wanting to tune in.'
He added that news networks drew large audiences in France and America and were 'rapidly becoming a crucial mainstay of the nation's consciousness'.
In an oblique reference to the campaign to save Radio 4 on long wave, Mr Birt said Radio 4 listeners 'were the most articulate and vociferous audience who protest vigorously at any prospect of change'. If the BBC wanted a quiet life, nothing would be changed at all.
But he said that Radio 4 was not perfect. 'In particular, it is skewed far too much in its concerns and its appeal towards the southern middle classes. Whilst losing nothing in range, intelligence and style, we need to broaden its base.'
Mr Birt made a similar criticism of Radio 3, saying that it should not be 'some elite club for the already initiated'.Reuse content