evidence: If the natural parents of the child are married or in a civil partnership, either the mother or the father can provide the required information to the registrar, who will register the birth. [...] If only the mother has parental responsibilities and rights towards the child, then only she has the right to choose the child’s names. She can call the child whatever she wishes. This means that in a mixed-sex couple, the mother can give the child the father’s surname if she chooses, even if they're not married. Choosing the father's name for the child isn't the same as registering him as the father of the child. [...] the natural mother doesn't have to give details of the father on the birth certificate. She can leave that part of the form blank the natural father can't register his name unless the mother agrees when both the natural mother and father agree to the father’s name being registered, they can go to the office together. However, if only one of the parents goes to the registrar’s office they have to have a document called a declaration, signed by the other parent, to prove that each agrees to the father’s name being added. There are special forms available at the registrar’s office to make the declaration the natural mother can register the father as the father if she has a court order declaring that he is the father.