Unwelcome Lodger

I would say the wisest course of actions is to lay low for the weeks notice. If you can and are able to change locks, go to a hardware and buy new ones.
After the end of the period has, when you cop that he has left to go to the shops or whatever, burst into action and change the locks and bag up all his stuff and leave it outside.
When he comes back from the shops just lay low. If he starts shouting or attempts to force entry, you are perfectly entitled to call the Gardaí at that point. And you are within your rights to defend yourself and you property if a legitimate need for force arises.

How on earth did you get saddled with this fool anyway? Did he seem normal at the start and then start to act the prick or what was it that caused the relationship to deteriorate.