Michael Jackson did not oppose plans for BBC Three

"The content will not even be down on paper yet," a spokesman said.

But he added: "Most people's guess would be that it will be about where Channel 4 is going."

As the BBC's director of television, Mr Thompson was responsible for rolling out the corporation's digital strategy.

He advanced plans for cultural channel BBC Four, which is now on air, and youth channel BBC Three, which is awaiting clearance from the Department for Culture, Media and Sport.

His Channel 4 predecessor, Michael Jackson, said the channel was not opposed to the plan for BBC Three.

'Soul'

But after Mr Jackson left and Mr Thompson took over, the channel changed its policy, saying that it felt a new youth-oriented digital channel would threaten its own offering, E4.

The high-profile MacTaggart lecture often generates controversy.

Two years ago, BBC director general Greg Dyke used the address to announce that the BBC One was moving its Nine O'Clock News to 10pm.

And ITV's head of programming, David Liddiment, last year warned that the "soul of television" was in danger from increased competitiveness.