PPL collects and distributes broadcast royalties from UK radio stations to Record companies (Master rights holders). Here is a link to the PPL website. PPL membership also gives a record company free access to the BPI’s anti piracy unit’s services. BPI APU can scour blog and torrent sights for unauthorised links to your repertoire and issue take-down requests.
In the UK PPL also distributes ISRC prefixes. All digital releases require a unique ISRC number for each track. More information can be found about ISRC here. Here is a list of international organisations who distribute ISRC prefixes (for labels based outside the UK)