The man in charge of BBC TV has said he expects to lose viewers when BBC3 moves online.
The plans for the channel, subject to approval by the BBC Trust, include moving into social media in a bid to attract audiences, but director of television Danny Cohen said he expected an initial dip in viewers.
Moving the channel online is expected to save £50m, and the vast majority of the new, smaller budget – 80% – will go on traditional comedy and documentaries, while 20% has been set aside for short films and digital media designed to draw in young viewers from sites including Tumblr, YouTube and Twitter.
The change will also allow the corporation to launch a BBC1 +1 channel and show two hours more of CBBC a night.
Mr Cohen told reporters: “We expect an initial drop overall and that’s why we want BBC1 and BBC2 to pick up the weight. It’s also why we see this as a package in our proposal to the trust for a BBC1 +1, because we know those +1 channels are very important to people.”
Director-general Tony Hall said it was part of a move to “transform the BBC for the digital age”.
He said: “By searching out new ways to engage and entertain young audiences on their terms, the new BBC3 will be a great example of how we can reinvent the public service for the digital world.”
The decision to move the channel is a controversial one – about 187,000 people signed an online petition opposing the move less than a week after the decision was made public.