A British mother and her son, who have admitted to having a sexual relationship, have gone into hiding following warnings they could face up to 15 years in prison.

Kim West, 51, and her son Ben Ford, 32, who live in Michigan, have been in a relationship since 2014 when they met for the first time since Ms West put her son up for adoption a week after he was born.

The couple are now in hiding after warnings from US authorities they would be forced to investigate their relationship if made aware of it by the public , according to the Mirror.

In Michigan state consensual incestual relationships between adults are a third degree felony punishable by up to 15 years in prison. Those convicted are required to sign the sex offenders register for life.

A spokeswoman for Michigan State police told the Mirror she was “not aware” of a complaint regarding to the couple.

Ms West, from Islington, became pregnant while studying in California and gave her son up for adoption aged 19, after which she returned to the UK.

In December 2013, Mr Ford – who at the time was married and living in Colorado – wrote to his mother in an attempt to track down his biological parents.

Two years later, Mr Ford, a freelance computer coder, left his wife and began to live with his mother in Michigan.

The pair told the New Day their relationship is not incest, but Genetic Sexual Attraction (GSA) – sexual attraction between close relatives who meet first at adults.

The term was coined in the late 1980s by Barbara Gonyo, the founder of Truth Seekers in Adoption, a Chicago-based support group for adoptees and their new found relatives.

In a book written about the subject, Ms Gonyo says romantic and erotic arousal maybe the delayed consequence of “missed bonding" that normally takes place between a mother and her new born infant, or between siblings, had they not been separated by adoption.

Ms West said: “This is not incest, it is GSA. We are like peas in a pod and are meant to be together.”

Mr Ford added: “When I met Kim, I couldn’t think of her as my mum but instead as a sexual being.

“I had seen a therapist at an adoption support group and had learnt about the GSA phenomenon.”