YouTube Music Key subscription service unveiled

Google's YouTube is starting a subscription service that allows users to stream ad-free music videos, and download them for offline use.

The monthly fee for Music Key also provides membership to Google Play All Access, the firm's pre-existing "all-you-can-eat" song download facility.

It is set to pose a challenge to Spotify, Rdio, Beats Music and other audio-only "unlimited" music services.

BBC technology correspondent Rory Cellan-Jones put the product to the test.