18 year old son has been great kid until he finished A levels in June and since then has had attitude that 'I'm 18, I'm leaving home soon and I can do as I like'. He's been a pain all summer. We have few house rules, are very close family, but the most basic rule is that boyfriends/girlfriends may stay over, but in spare room. Last weekend we were away and made it plain to kids (after party last time they were left alone) that we were locking up and they had to stay with grandparents - we didn't want any of them in house. Son told GPs load of lies about where he was going, disappeared for two days and basically let himself into our house and spent weekend with a girl he had picked up. He then left for new job 100 miles away. We were fuming. He came home Fri night, was a bit shame faced when we told him how furious we were then went out Sat and returned (after we were in bed) with same girl and took her to bed. I got up for a drink, realised situation and knocked on his door and told him she was to be out in 5 mins. He then left with her. When he returned today I told him to pack his stuff, he was no longer welcome in our home as he couldn't obey the rules and I would drive him to his new flat. He basically couldn't give a monkeys. I've told him he is welcome to phone and visit but that we won't have him stay over again until he apologises and agrees to respect our house rules. His younger brothers and sisters are devastated and keep saying 'can't he stay here anymore?' The answer is 'no, he can't'. I'm furious, hurt, upset and terrified that he won't bother keep in touch, but he has just become so arrogant and cocky that I can't bear it. I don't see why I should let him do as he likes in my home. Advice/opinions anyone?