Speaking at a forum of European broadcasters in Birmingham, Mr Birt warned that the introduction of multi-channel digital television could destroy Britain's national identity and culture.
He said: "The consumer will be increasingly asked to pay directly for what they see. The cost of watching a screen will rise enormously. We will see the emergence of the information rich, and the information poor. We risk a knowledge underclass."
But he added that on the eve of the digital age, the Government should ensure that public service broadcasting remains openly available to all.
The race for digital supremacy is already on, and Rupert Murdoch's BSkyB looks set to be the first to broadcast in the new multi-channel format. At present, all televisions are analogue.
But Mr Birt has pledged that the BBC is not far behind and gearing up to provide a full and varied service in digital.
He said: "At the heart of the public broadcasting tradition is universality - reaching out to ever household in the land - the poor and the prosperous - offering enriching experience and information which extends understanding.
"Public service broadcasters seek not only to delight, but to give individuals the knowledge they need to live fuller, more satisfying lives."
He went on: "The ubiquitous soft-drink world of jeans, trainers and the baseball cap will advance inexorably. We cannot halt the advance with barriers or quotas. Nor should we - one of the glories of the modern world is being exposed to the best of other cultures.
"Rather, the drive of public policy should be to sustain individual national cultures. There is no more effective way of doing that than by encouraging a flourishing public service sector in each [European Union] member country."
He added: "In the space of 12 months or so, the BBC will have introduced three new publicly-funded channels, focused on news, learning and enhancing our existing services."
He highlighted BBC News Online, an Internet Web-site which carries material from the World Service and other BBC specialist journalists, which he described as "a wonderful research tool".
He went on: "EU governments need to be energetic to ensure that they have the necessary digital network infrastructure, that all children at school and people at work acquire skills they will need to get the most out of their personal lives and to work effectively."
Mr Birt also hinted at his fears over the power of BSkyB and Rupert Murdoch, as digital television looks likely to hit the high street stores in a year's time.
He said: "We will need effective regulation of the digital gateway at national and EU levels to avert dominance of powerful gateway controllers - those who control access to digital screens - and to encourage openness of digital systems to a diversity of voices and a plurality of provision.
"Public broadcasters have a critical role to play in raising consciousness about these matters, and through our educational services, enabling individuals to acquire the necessary skills.
"The BBC will play its part in the UK. But unless everyone, and most especially government, puts their shoulders to the wheel and tries to advance the digital society, we shall take too long to achieve lift-off."Reuse content