The BBC could cut back on its overnight programming in a bid to save money.
The move, which would affect the schedule between 10.35pm and 6am, is one of the ideas suggested by the corporation's staff in an internal review.
The BBC currently spends £150 million a year on overnight programming.
Director General Mark Thompson said the BBC was looking to see if there was a case for investing less in off-peak programming and more on peak-time shows.
Asked if overnight programming could disappear altogether, he said: "Obviously that's one theoretical possibility or you might do something else, you might put something else on."
He added: "In a sense, it's more of a question it seems to me of how much money, how much of the licence fee, should you direct to this part of the schedule given the people available to view?
"Why is the money where it is? Is there a way of filling this part of the schedule for less money?"
The BBC committed itself to saving billions of pounds from its budget when it launched the process, called Putting Quality First, last year.
Other ideas, which the BBC described as "common emerging themes" from the process include repeating its popular shows like the drama South Riding on different channels in the same week.
Mr Thompson said he had not made any judgments yet on the responses to what he described as a "set of open questions" and admitted some of the ideas would not "fly".
But he said it was "unlikely" there would be proposals for the complete closure of services.
Recent speculation suggested the corporation is considering cuts to its local radio output and replacing BBC2 daytime shows with news.
The BBC initially announced it would close digital radio stations 6 Music and the Asian Network in an attempt to find savings but has since stepped back from that.
Mr Thompson said he hoped increased costs, brought on by inflation and taking responsibility for the World Service and Monitoring as part of the deal that saw the licence fee frozen for six years, would be met by savings, an increase in the numbers of households paying the licence fee and reduced collection costs.
The final proposals will be submitted to the BBC Trust for approval in July.
A National Audit Office report published today found the BBC was doing "a good job" in controlling costs in the making of its soaps.
The report found it spent £102.5 million making six continuing dramas or soap operas, down from £108.6 million in 2002-03.
The shows include Casualty, EastEnders and Holby City as well as Scottish show River City and Welsh-language drama Pobol y Cwm.
NAO head Amyas Morse said: "The BBC is doing a good job of applying basic financial controls and achieving steady cost reduction across its portfolio of continuing dramas."
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