These commercially licensable recordings are free for non-commercial use, as long as users credit where they came from. “Mixer mode” allows users to “layer, edit and re-order clips from the archive to create your own sounds” to create rich, unique soundscapes.
“These include clips made by the BBC Radiophonic workshop, recordings from the Blitz in London, special effects made for BBC TV and Radio productions, as well as 15,000 recordings from the Natural History Unit archive. You can explore sounds from every continent — from the college bells ringing in Oxford to a Patagonian waterfall — or listen to a submarine klaxon or the sound of a 1969 Ford Cortina door slamming shut.”
You can access the BBC Sound Effects Archive here.
Source: Open Culture