Tessa Jowell yesterday warned the BBC it faces tough new scrutiny if it is to continue justifying its licence fee.
The Culture Secretary, who has recently angered the corporation's commercial rivals by agreeing to a string of new services - including BBC3 and its digital curriculum - said a question mark would be thrown over whether the BBC was making the best use of its public funding before the Government decided to extend the terms of the corporation's charter, due for renewal in 2006.
Jowell told a media conference: "Charter renewal gives us the opportunity to look at the heart of the public service broadcasting system.
"It gives us the chance to ask whether the BBC can continue to be the driving force behind public service broadcasting. To ask what shape the BBC should be. To ask what range of programmes it should provide. To ask how it should be accountable to its audiences."
Critics, including former BBC director of television Mark Thompson, now chief executive of Channel 4, yesterday challenged the BBC to reveal what further plans it has for what many in the commercial sector feel is unfair encroachment into their territory, backed by the licence-payer.
Thompson compared the BBC's march towards ever greater broadcasting power to a US military operation, telling the same conference: "One of the biggest challenges the BBC faces is the very widespread - justified or unjustified - sense of what the US military call 'mission creep'."
Meanwhile, Ofcom chair Lord David Currie told the conference he hoped the advertising industry could come up with proposals for a "co-regulatory" system, allowing Ofcom to find a balance between industry self-regulation and "club-wielding".
Jowell also used yesterday's conference in Oxford, organized by The Guardian, to announce the Government was accepting the vast majority of proposals made by the ITC to amend the Communications Bill to protect ITV and Five from an influx of cheap imported programming in the event of either being bought by foreign companies.
The Government will also propose guidelines protecting the rights of independent producers.