physical and verbal abuse from my 14yr old son

hallo I am carol and this is my first discussion piece.  I'm not coping very well with parenting my teeange son, who both physically and verbally abuses both myself and my daughter of 12.  I've called the police out that many times they've warned me in a polite way the next time for both mine and my daughter's sake they will arrest him.  I find it hard to pick up the phone and call them because of this but in the past 2 weeks have had cause to many times.  I dont want to give him a criminal record for the rest of his life but I also am absolutely exhausted with trying to resolve the issues.  This has been my way of life for a year now and both social services police womens aid counsellors and other agencies have been contacted as I've been very proactive in trying to get support for myself and help for him too.  so far nothing i've done has changed the situation but i do continue to get support from womens aid and my counsellor.  social services have been almost entirely useless in my situation and have now got no respect for the organisation as a whole.