It sounds as if your son is in a negative spiral of bad behaviour. He now has a reputation of acting up and so is living up to it. he may also be doing it as a way of gaining attention. Talk to his teacher about setting up a positive behaviour chart, where ALL good behaviour is noticed and rewarded, and negative behaviour is mostly played down. This way he gets the most attention from being good, and very little from being naughty. Children crave attention and this really works. I'm a teacher myself and I promise you it does.
Also ask for a contact book where your teacher writes a couple of sentences about how he has been each day - making sure she writes about the good days as well as the bad! You could also write how he has been at home - your son will be thrilled to show his teacher what a good boy he is at home. Put smiley faces in it for good days and ask his teacher to do the same, then promise him a reward when he gets a certain amount (keep this small at first - maybe 3, then the next time tell him he needs 5, then 8 etc). Let him choose the reward at the start of each goal so that he something to work towards and look forward to. Be very consistent and don't be afraid to give him lots of praise for good behaviour. He will love it and it will boost his self esteem and improve his behaviour.
You might also need to teach him how to avoid tricky situations which get him into trouble, especially if he is being influenced by other children. Talk to him about why he does what he does and help him to think of ways of avoiding being naughty (it is better if he thinks of these himself, with a little guidance).

Remember, children (and adults!) love attention and positive rewards and praise - these are your best tools.
Good luck! :)

Heelo!!
Do you or have you considered volunterring in your son's classroom? I have seen many childrens behacior in school improve when their Mom is present at school (like once a week or so). Maybe you could go have lunch with him once in a while during his lunch break. Showing him how important school is to you will help him to improve.

Hi, Thanks for the advice. I do go into school twice a week and help out in class. Thursday I listen to children read and help those children who are struggling. On friday I help out with art which is enjoyable. I find that because I go into help the Teachers come to me with Ryans problems. But this is sometime too much as they only point out his negative behaviour. We as a family a banned the playstation and gamecube, and have been playing family games ie scrabble and monopoly and going back to basic toys like lego. I have also cut out all junk foods and have been doing alot of family meals and baking. So its a cake instead of a bag of crisps. Then at the weekend if things have gone well he is allowed an hour on the cube. But then making sure we do family things together. I never had problems when I was small and I do feel that maybe going back to basics will help. Ryan has enjoyed peeling potatoes and preparing meals with me. I don't think children talk as much as they used to. So Im trying to engage him in conversation, trying to talk about things he interested in. Obviously I don't not talk to my child but I think now days we do tend to let them get on with things rather than joining in with things. Any advice that you can give me further will be much appreciated.