I actually woke up in the early hours last night worrying about the havoc just one commenter is wreaking on our site.
He used to be called Angry from Purley, and we managed to ban him for a while - but he seems to have got a new IP address, and is back, under a range of pseudonyms.
Unfortunately, at the moment, we can't ban him. Our last message management system gave us his IP address, but you couldn't ban him using it - our new one has an effective banning system, but generates the same IP address for every unregistered commenter (which led to editor Ian Carter accidentally banning everyone from commenting the other day - oops). It's something we are asking IT to look into urgently.
Fortunately, I don't think he's worked this out yet. Unfortunately, he's steadily building back up to his worst self, and yesterday posted a whole load of highly racist messages under the name of our troll-magnet.
I am really not sure he intends to be such a site-wrecker. He seems desperate to get an apology for banning him in the first place (while not wanting to admit it's him in case he's banned again), which seems to indicate he wants to be part of the community.
There's no way we're going to registered comments only though. There's far too much value from people visiting the site for the first time about an incident they've got info on, then commenting with that insider knowledge - they wouldn't do that if they had to spend 5 minutes filling in a form.
I just hope our IT bods can pull their fingers out and get this fixed fast.