http://www.mpsonline.org.uk/mpsr/

If you live in the UK and want to stop junk mail being posted to your address then this is the site for you. It’s not 100% effective but it’s better than nothing.

“The Mailing Preference Service (MPS) is a free service set up in 1983 and funded by the direct mail industry to enable consumers to have their names and home addresses in the UK removed from lists used by the industry. It is actively supported by the Royal Mail and all directly involved trade associations and fully supported by The Information Commissioners Office (ICO).”