I received a letter that has "Important Documents Enclosed" written on the outside. If the documents were important, surely the sender would prefer anonymity? I looked at the return address, and it appears to be from a direct mail company:
Direct Works, Unit 1/Union Park/Bircholt Rd, Maidstone, ME15 9XT
Direct mail is also derogatively known as spam, as defined
here.
I'm going to stick it back in the post box and see what happens.