There is also the Junk Mail that the Post Office are paid to dump in my letter box. Every week or so there is the heap of flyers that get dropped through my letterbox along with the post. Mainly local discount shops, and takeaways.
If you want to stop this it is like some Hitch Hiker's Guide joke. IF you persevere you can find a page buried on the PO website that allows you to opt out of getting these leaflets. BUT the catch is it takes "up to 28 days" to opt-out. And then the opt-out is only valid for three months... and then the just ignore you and start they junk drops again.
My favourite trick with junk mail is to take each junk leaflet, find an address, then get an envelope and fill it with random rubbish - ideally heavy like the Yellow Pages \ Phone Book. Address it to the sender of the junk mail... and forget to add any stamps. This leads the spammer to get a parcel delivered... but lack of stamps means he has to pay extra. I call it recycling.