I've about 200 Facebook "friends" (all people that I do know to say hi to in real life), but can only see 70 or so.
He is a member of my cricket club, which had a standard everybody-friend-everbody-on-FB session years back. I'm surprised I didn't think to delete him on that last message to be honest, but he will be gone soon enough.
Given that your description of him is '...a pretentious, spotty, ugly, annoying little fuck...' why would you keep him on your Facebook thing?
Simple rule - if a person asked you to go for a cup of tea in town when you have nothing better to do, if there's any hesitation in you saying "yes", then you block them. Facebook actually becomes useful/good then.