The plan, being considered as part of the commissioning and production review ordered by director general Mark Thompson in June, is already causing alarm among in-house producers.
One senior executive has even described it as a 'perfect storm' that could 'destroy' in-house production.
Broadcast has learned that the BBC is looking at plans for what it calls a 'window of creative competition', or WOCC, that could see 25% of the BBC's programming hours opened up to all comers. This would mean external producers such as indies, companies owned by broadcasters, such as Granada, and American studios all pitching alongside in-house BBC producers.
To make room for the change, in-house production would be capped at 50% of hours, compared to its current 75%. Indies would retain their 25% quota.
A senior BBC source confirmed the WOCC proposal was being looked at seriously and had been given a 'lot of thought', although no exact figures had yet been discussed.
However, London-based in-house staff, particularly in factual and learning, fear they would bear the brunt of cuts as the BBC would be unlikely to cut its regional commitments.
'It could destroy in-house production in London,' said one BBC producer. 'The feeling is that in Mark Thompson's willingness not to have a BBC that is big, he is prepared to consider radical solutions that might end up destroying the whole reason why the BBC exists. People really are in despair.'
Thompson hinted at the plan at a Royal Television Society conference last week. 'I think the idea of opening up a zone of genuinely competitive space to the independent sector and to the best of our in-house producers is something we want to do,' he said.
John McVay, chief executive of producers' alliance Pact, also supports the move. 'We want proper competition in programme supply,' he said. 'The BBC is very engaged in talking to us. It clearly recognises it is an area it is going to have to look at.'
As well as WOCC, Thompson is understood to be looking at introducing a concept of 'batch commissioning', in which major indies and key in-house executive producers would be given their own budgets and commissioning hours.
Thompson has told colleagues he wants to cut the number of commissioning decisions to slash costs and speed up the system.
The move would be part of a major shake-up of the current 'double tick' commissioning structure, which is currently being reviewed by head of current affairs Peter Horrocks.
On Wednesday (6 October), it was announced that BBC director of strategy and distribution Carolyn Fairbairn, who is leading the commissioning and production review, is to leave the corporation after seven years to go travelling with her family.