I have had my nephew living with me for 3 months how can I get custady over him his mother doesn't won't him and his father hasn't got the space.. or she has said she will sign all rights to me but how do I do this without social services taking him away ?

If you are going to adopt him or have his mother and father appoint you guardian, you hire an attorney, he does all the paper work, have BOTH parents sign and it is filed in court.