Can My Child’s Father Prevent Me From Taking Her Back To The Us?

Location: UK. My child and I are American citizens with American passports, my child’s father is British.

Basically, our child was born in the US where I am from. We came on an extended visit to the UK, and it now looks like we are going to be separating.

I have no interest in trying to keep my child’s father from seeing them whenever and however he would like to going forward, but now he’s threatening to do everything he can to prevent me from taking our child back to the US with me. I’m worried his mother will try to help him fight me.

For context, we’re not legally married but he is on her birth certificate. Any advice or guidance would be greatly appreciated so I know what to expect if I end up needing an attorney. Thank you so much.

Edit: Thank you very much to everyone who’s given me advice. I’m extremely grateful and appreciate it very much. The consensus here seems to be that I should contact a lawyer who can give me the final verdict on this, however I’m completely (and I do mean completely) broke and cannot afford a consult fee. My parents are helpful and supportive, but if I indicate to them that I need to leave before I’m literally on my way they will freak out and rain the wrath of god down on my child’s father and his family and it could make everything a lot more complicated and volatile than it needs to be at this very moment, especially if I end up needing to leave in secret.

I’m going to do some research into resources for pro bono consults here, but if anyone has any ideas or can point me in the right direction in that regard it would of course help a lot. Thank you again xx