Say, for example a person was in a bad relationship, a non violent (as yet) but highly critical, verbally abusive, mentally abusive, controlling relationship where the male partner drinks to excess and the female partner dreads the afternoon as it gets closer and closer to the time he will be home. As well as having her own older DC she also has a small baby, her current partner is this childs father and on the birth certificate.
The female realises she needs to end the relationship but is scared to do so - mainly because he has told her repeatidly that he would take the baby away (baby is less than 3 months old and breastfed). She believes that he would 100% take the baby. He would take him from her arms even, or the second she turned her back. He would take him from his bed in the middle of the night, or from the pram when out walking. If he was locked out he would find a way to get in. He is on the babys birth certificate and has parental responsibility. He wouldn't hurt the baby.
What could the female do to pre-emptivily stop this happening? How could she be sure that she wouldn't lose her child? Is there any way of getting anything down on paper saying that he can't take the child away without him knowing that she has done it?