Surely not delivering the mail is illegal?
The Royal Mail is a crown company, and operates under the authority of the Queen. As such, all mail is the property of The Queen (I think there's an old offence, still on the statute books that say that delaying the Queens mail is an offence, under this rule, technically Royal Mail vans can go through red lights and if you don't let a Royal Mail out in traffic, you could be breaking that law!!!) and therefore, if you bin or destroy the leaflets then you are technically damaging the Queens property, which I'm sure carries a hefty sentence.
Obviously, it's not going to happen that any posties that refuse to deliver the mail will be charged with damaging the Queens property, but thought I'd mention it for the purposes of useless information for use down the pub.