Spouse visa to UK with child from previous marriage

Hi! I am going to be applying for a visa to the UK to join my husband there (a UK born national). I live in the USA now and have a child that is 7 from a previous marriage. What are the requirements/process for my son to also obtain a visa? In the divorce from my son's father I have full custodial responsibility of my son. His father never sees him, never calls him, NOTHING, & does not even pay child support actively. Basically, my son's father is NOT a part of my son's life at all.

My UK husband and I got married recently and we are going to be looking at moving to the UK on a visa, but I am just a little confused about the whole thing... I am guessing that I will apply for a spouse visa to join my husband, but what about my son? Is he included on this visa? Or do we need a separate visa for him? Will I need to obtain consent from my child's father for the visa?

See also Guidance.

You will apply for a spouse visa.
Your son will apply for a child settlement visa.
Show that you have sole responsibility for child.

Thanks Vinny, do you know if the divorce papers stating that I have sole custodial responsibility would be enough??