The guy who did a paternity test on his kids who were spread across different ages, and found out he wasn't the biological father to any of them. His wife wouldn't admit to cheating throughout their marriage, and then after a few updates she committed suicide.

This is why UK courts operate purely on the basis of what is best for the kids. Even if you find out you are not the father you will still have to pay child maintenance:

When the Child Maintenance Service assumes who the parent is You’ll be assumed to be the child’s parent if any of the following apply:

• you were married to, or the civil partner of, the child’s mother at any time between the conception and birth of the child (unless the child is adopted)
• you’re named on the child’s birth certificate (unless the child is adopted)
• you legally adopted the child
• you’re named in a court order as the parent when the child was born to a surrogate mother