I'm sorry, but I have to remove this post for falling foul of our twenty-year rule, since the answer to your question as phrased only begins with the creation of the BBC World news channel in 1995.

If you want to resubmit, it would have to be a question about the development of the BBC's news division prior to 1994, which would inevitably make it a question not about the BBC as a news agency but about one arm of a primarily domestic service.