This will include video, online programme extensions and clips, pics, blogs, vlogs, podcasts, quizzes, guides, games and apps.
The source added that the BBC is exploring how new technologies can enhance how children and adults discover new content, which is one area in which the broadcaster could one-up Amazon and Netflix, whose programme discovery interfaces are notoriously useless.
Tony Hall, director general United Kingdom pubcaster the BBC, has made it a priority to combat the growing influence of US-based subscription VOD services, and today's announcement ties into that narrative.
"We put children's front and centre throughout the charter renewal process and today's announcement reflects our commitment to our youngest audiences", said Hall.More news: Bank of England staff vote for strike action
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New investment in children's services is being funded by savings at the BBC. It will ensure that the BBC continues to reach as many children as possible with quality, commercial-free, public service content and interactivity that informs, educates and entertains. These features will go alongside traditional BBC kids television channels like BBC Bitesize, for education, and the hilariously named CBeebies, for ages six and under.
This new investment will enable the BBC to reinvent how it serves its youngest audience in the years ahead. "Creating a BBC uniquely tailored to each person is vital to that".
The plan, setting out the BBC's ambition for the coming year, will also set out how the Corporation will respond to other challenges, such as fake news.
Beano favourite Dennis the Menace will have a new cast of feisty female pals when he returns to CBBC later this year. Freddie Fox is the voice of mischief-making Dennis.