puddicat your son sounds just like my younger brother,our parents split when he was about the same age and he like your son was in and out of trouble for years, but there is hope - my mother stuck by him which was not easy for her.
My brother now say's that he was a grade one spoilt brat, using the divorce as an excuse, but he now realises that he did know right from wrong but chose do as he pleased!
You are not responsible for your son's behaviour and try to make him aware that what ever you do in life has consequence's, if you can stand by him - and as with my brother he will turn out to be a hard working loving son.
He must have some great qualities try to get him to focus on his good point's ,my brother always felt he was good for nothing but 'he has a good job and a family that stood by him even when he drove us mad which has paid dividends.
Good luck to both you and your son.