The NSPCC is calling for a loophole in the Position of Trust law to be closed, so the likes of sports coaches and faith leaders cannot influence older teens into sexual acts.
The charity's Close the Loophole campaign calls for all adults working with children to be covered by the law, so young people are protected in all activities.
At present only people like teachers, care workers and youth justice workers are legally in a position of trust, meaning it is against the law for them to have sex with 16 or 17-year-olds that they supervise.
It comes after 37 complaints were made to Northamptonshire County Council since 2014 about adults who abused their authority over teenagers aged over 16, in order to coerce them into sex acts. But police had no power to investigate in any of the cases because the adult's role is not covered by Position of Trust laws.
The NSPCC said hundreds of such complaints were made to councils across the country about positions such as faith leader and sports coach which were not covered by laws.
Peter Wanless, NSPCC Chief Executive, said: “It is absolutely outrageous that the law protects children in the classroom, but not on the sports pitch, or in a whole host of other activities.
“Government promised to extend these laws to sports coaches, but we’ve yet to see action and I fear they are backtracking.
“Any extension of the law must apply to all adults working with young people. To keep children safe this loophole must be closed – it is not enough to simply make the loophole smaller.”
Councils recorded the adults' jobs or volunteer roles in 495 cases. Of these 31 per cent of cases were about adults working in sports settings, 14 per cent related to adults in faith settings and 11 per cent related to youth work.
'Megan', an elite athlete, reported being targeted by her sports coach Will*, who was in his thirties and had been training her since she was 13 years old.
When she turned 16 Megan says he began sending her sexual messages, before starting a sexual relationship with her when she was 17.
Will received a temporary coaching ban but because sports coaches aren't covered by the criminal law, police were not in a position to bring charges against him.
Megan said: “We used to speak on webcam and he would ask me to do sexual things but I said no. He would go in a mood when I said no.
“He carried on coaching me and would pick me up first and drop me off last so we’d be alone together in his car or van. He’d pull over somewhere quiet and that’s when things would happen.
“I was 17 when we first kissed. We didn’t have sex but we did other things. After that happened, he selected me for his other club.
“It was a secret so I felt like I had to delete all of our messages. It didn’t feel nice to keep it a secret because it felt like I was lying. There were a lot of feelings of guilt involved.”
In November last year, former Sports Minister Tracey Crouch announced that the then Department for Culture Media and Sport and the Ministry of Justice had agreed that Position of Trust laws would be extended to sports coaches.
But no action has been taken, and the Ministry of Justice has since written to the NSPCC, with the charity gaining the impression that the Government believes laws on the age of consent and on non-consensual sexual activity provide adequate protection for 16 and 17-year-olds who are preyed upon by adults who supervise them.
To sign up as a campaigner for the NSPCC’s Close the Loophole campaign, click here.