Carole Horlock is probably Britain’s most prolific surrogate mother. She gestated and gave away 13 babies before hanging up her boots in 2012 at the age of 49.

But she has revealed that she inadvertently gave away one of her own children. She told the TV show Good Morning Britain that in June 2004 she gave birth to a 9lb 4oz boy which she believed to have been conceived with her egg and the sperm of her client. However, after 6 weeks, the commissioning couple did a DNA test and discovered that the baby was actually the child of Horlock and her husband Paul.

Carole and Paul still agreed to adopt out the baby. It was an agonizing decision for them. For each of them, it was a second marriage and they had agreed not to have children. But it was still a wrench:

“This little boy was accidentally created with an act of love between my partner and I. We didn’t know it when we handed him over. “We agonised over what to do, but in the end decided to let them keep him.

“People have asked, ‘How could you give this baby away as this one is yours?’, but many of the surrogate babies I have given away have been mine biologically. The difference was he was also Paul’s. We have never stopped thinking about him. We live in hope he is aware of us and, when he turns 18, he’d like to see us.”

They kept in touch with the other couple for a few years, but eventually they fell out of touch. Carole told The Mirror: ““I am in contact with almost all of my surrogate babies – but not him. As the years pass we think about him all the time. Paul has developed a heart condition and it would break my heart if he never met him.”