What's it all about, then?
Writers and photographers are entitled to extra money from companies and organisations that photocopy their work. To be sure of receiving this, and other payments for such "secondary uses" UK freelances need to register with ALCS (for writers) and/or DACS (for photographers, illustrators, etc).
How these payments generally work is that libraries, press offices and others who do bulk copying pay a licence fee to the collecting society. This arranges a survey of a sample of licensees, to work out statistically how to distribute it. Efforts continue to deliver the share of this money due to newspapers' contributors.
These "collecting societies" also distribute money collected for secondary uses in other countries - including, for example, Public Lending Right from Germany and the Netherlands.