BBC Radioplay Music - What is this?

We know about Radio Station records and this site has a complete section on Radio Station records related to Chuck Berry. So far my knowledge was that these records were used to distribute pre-recorded radio shows to the many FM radio stations throughout the USA.
To my surprise I recently found a non-US radio station album. Or at least an album of which I think is a non-US radio station album. In contrast to the US albums, the record Let It Rock (BBC Radioplay TAIR 87059) shown below has a printed cover containing details about each song, liner notes about the artists and even a drawing up-front which seems to show Chuck Berry. There are five Berry recordings, four by Bo Diddley and a few by Clarence Henry, Dale Hawkins, Bobby Charles, and Paul Gayten.
The record's publisher is listed as BBC Radioplay Music Library. The back cover includes the note "BBC Radioplay Music is not available to the public".
Can any reader shed some light on this release? It seems to be correct that the record was not sold commercially as there are very few out there. However, why would the BBC create a sampler for their own internal use? And why would they spend the money to create and print a complete album cover and label only for a library issue? Let me know if you know anything about this or other BBC Radioplay releases.