Fronted with Eric Gill's statues of Prospero and Ariel, from Shakespeare's The Tempest, the building was built for the BBC, and was the UK's first purpose-built broadcasting facility, including 22 sound-proofed studios.
Broadcasting House is home to Radios 3, 4 and 7 and also houses the BBC Radio Theatre, which your author featured back in January last year. Whilst the building is currently undertaking a major redevelopment, expected to be finished in 2011, it remains largely intact, and operational, with some building to the rear to accomodate the anticipated arrival of BBC News from the News Centre at Television Centre.
The building is not constantly open to the public, but there are occasional tours, which are available for about a tenner, and you can get in by listening to a radio recording (see link above). For more on the tours, see http://www.bbc.co.uk/tours/bh_london.shtml