toothache,
I am on MN occasioanlly but your story remind me of mine. I think I can answer your question about using the drugs as a legal argument in court if you get there over contact
With regards to drug detection, there is a test that court can order, on the parent's hair. Apparently as long as hair is not cut, traces of the drug will stay. My solicitor told me this when we were discussing what line to take if ex-h took me to court over access to dd.
If you continue to deny access, it is up to him to do seek access via the courts. There is nothing you can do until then. If he does, then there will be an investigation and as part of this your solicitor can request this test, or the court.
What the solicitor kept saying is that law take the interest of the child first, and in general, the law takes the view that it is in the interest of the child to know the father, no matter how bad he is, (drugs, and worse), and they would suggest supervised centre visit where the fathrer can see the children, if there is no other alternative.
Obvioulsy the father has to be very violent for the court to totally exclude him.
I was really frustrated to learn this because my ex was very bad to have around, he stole from us for his drugs, totally wasted in front of his child, when left alone with dd he made himslef unsconscius with drugs and thats when I totally excluded him. Other issues lead the court to issue an injunction to stop harrassing us.
in the end he did not persue contact with the courts because he so demented with drugs that he does not have the brain and it isn not his priority. but if he did, he would have had a good chance to have some sort of contact, even if he was that bad and I really cannot see how this could be in my dd intersts. probably some lawyer in here can explain the law better than me, I think I got the gist right though.
My heart goes out to you.