I really don't know what to do now, with my housemate from hell

So this is a difficult one. I have lived in my rented accommodation since July, and at first it was perfect rent is reasonable it is close to college/work, house is not damp, I got on quite well with everyone 3 other guys,and one of them is a close friend.
since late September things started to go a bit awry,it resulted in me not bringing friends to the house, I am the only female and I am in my late 20's, the horror in question is only 2 years younger than me.
so one night at the end of October my housemate got wasted on a bottle of spirits, him being drunk is nothing new it is a daily occurrence, but this was the worse he has been, I came in from a friends house and went into the sitting room he started ranting at me and it was quite terrifying, he started to say a lot of personal things about me, attacking the very core of who I am then started spouting a lot of strange things about his childhood and women, then started saying that he didn't trust me because I had periods... yes I know.

anyway I just was in shock and I didn't reply to much I just said I was sorry he felt that way and I walked off in total disgust. I did not want to deal with him any more so it was a few days before I seen him again. when I did see him again he apologized and said he did not remember any of it, and that he would never let it happen again. so I just gave him another chance, and accepted his apology, still I was wary of him after that, then he landed home with a present for me, and said sorry again and it seemed sincere.

so he continue's to drink after this not as bad, but making sly comments when ever I got stuck in the sitting room with him on my own. never in front of the other guys just making sexist comments when it was just me.
another time I was at a friends birthday and his friend was there, so thats when I found out he had said to his friend, that I had a major problem with our other housemate, his friend let it slip because he had brought my housemate and was like oh I am sorry I know you don't like him, when I asked him what he meant he had no choice but to tell me what had been said, I don't have a problem with him at all, I get on very well with him.

I was just avoiding him like the plague he is, and then my friend came to visit for a workshop and he shouted at him and scared him, very inexcusable in my mind what ever about me which is bad enough but my friend should have been made to feel safe. my friend is leaving and then he says sorry again to me and my friend and wouldn't even allow us to say goodbye to each other because he keep saying sorry but in a bullish way that just seemed chaotic. again he said it would never happen again. which is bull****.

so before I left for christmas he started standing in front of me blocking my way, as I was coming into the house, he has done this a few times now, I am scared of him, locking my room when I am in the house alone with him, I have no idea what hes going to do next I feel unsafe in my house and I want to move out but its next to impossible to find a place.

He never cleans up after himself he leaves his **** everywhere and he sleeps on the sitting room sofa most of the time instead of his room.

I have talked to both my other housemates about whats been going on, one of them has been getting hassle of him as well. My other housemate said he would sit down with me in the new year and just make sure he listens and does not dismiss me anymore.
I have a feeling he won't take it to well.

I wonder what my rights are in terms of talking to the landlord and just getting him to move out. I feel so angry and upset at this situation I feel like I should not move out and hold my ground, as we are all paying the same rent, but I also fear for my safety and don't want to be putting myself in harms way.

any advice would be gratefully appreciated