1. Fill out this form2. Your name will go on a list3. Every month (or every couple of weeks, depending on the length of the list) a name will be chosen at random4. If it's your name, you'll receive an email letting you know5. Not too long after that, Royal Mail permitting, you'll get a letter from me.
Aaaand ... that's it. Obviously, I will keep all personal information confidential and not turn up uninvited on your doorstep with an axe or anything.
You can sign up for this from anywhere in the world: UK, EU, International, interstellar. As long as you can receive post.