Talk

Get all his stuff out the lounge yourself, and tell him your rules or go get his own house. If he's violent or aggressive towards you, call the police.

He's an adult. Why can't he move out? He doesn't get to steal your stuff and verbally abuse you.

It's not his house - it's yours.

I have a son this age and he would not dream of being rude to his parents or swearing at us. It simply would not happen.

You need to sit down with him and explain what is acceptable.

He's legally an adult now. If he doesn't want to live by YOUR rules, in YOUR house then ask him to leave and find his own place.

Did this and it all came back again!

Did what?
He needs to act like the adult he is supposed to be and treat you and your home with some respect or leave.

I have done this on many occasions and it still has not worked. Have also explained the 'my house' rules. Am divorced and house not yet 100% mine so he reminds me of this. Ex is not interested so cant talk about it to him. He is ruder than all of his friends and some have said to their parents that they think he is wrong. So hard...

You have done what? Kicked him out?

If that was my son behaving like that I would have chucked the Xbox laptop and tv out of the window ideally an upstairs one. He can't put it back in the lounge if it's broken.

He's using aggression to bully you. I recognise it as my mum has been through the same scenario with my brother (who is much older than 18 and should be ashamed of himself frankly ).

So, you either put up with it, or stand up for yourself. Change the wifi password or move his stuff back and put a lock on the living room door. The nicely nicely approach isn't going to work I'm afraid .

Who cares that the house is not 100% yours. If your name is on it and his is not then you can and should have him removed! Just because his dad's name is on it, it doesn't mean HE has a right to live there. The police will help. He's old enough to live in his own now.

Thank you to everyone - you have all confirmed exactly what I thought and believe! Thought I was going potty but I have not thrown him out as that is the last resort - not yet anyway. I have moved his stuff before and have just done it again this morning and told him yet again that I will take it all away if it comes back and I will. He said I am embarrassing myself and some other disgusting expletives. I also told him he is free to move out - again. He will not because he knows it is better living with me...

My son is the same apart from he is only 14yrs!! I've tried everything from being really nice to being really firm and nothing works. I feel for you

It is hard because they are still our children. You do not want to be horrible to them. However, there comes a time, as I have discovered that enough is enough. My son has steadily got worse. His last year at school (GCSE's) was not great but he did really well. First year of 6th form was also not great and he did not do great. He is at another 6th form and re-doing last year. School is fine but his home behaviour has got worse and to be honest I don't really know why. Either I missed the signs or blissfully ignored them. So this is where I am now. Everyone who has commented has said the same and I agree with them. I should have dealt with it earlier, not my fault but I let it happen. At 14 years I think that you can still get intervention help. My son is now an adult and this needs to stop now.

But you keep giving him ultimatums and caving in? So he thinks he can walk all over you? You're supporting him through education and he's treating you like shit? Time to man up and earn his own money. He's not a child.

Is there another adult in the household(or well respected friend)that can tell him to behave? Does he have personal finances(student/working)?
Has he just changed (influenced by outside forces)? Its nice to understand behaviour and work to bring him into civilised behaviour , but if hes a brattish man then treat him like one.

I did not cave in but did not make good enough ultimatums! He did have a part time job but was 'influenced' into giving it up by someone and yes this person is unfortunately assisting him in this change and that is why there is no other adult in the house.
He is beginning to turn into a 'brattish man' and I have to try my best to change this without giving in.

An ultimatum can't be not good enough. I suggest you've never actually given an ultimatum.