The number of child sexual exploitation victims counselled by Childline has risen by 16% in a year, with perpetrators believed to be increasingly preying on targets online.

The NSPCC’s round-the-clock service delivered 4,500 counselling sessions in 2018-19 to children and young people who were coerced or forced into sexual activity, with the youngest victim aged just nine.

The head of Childline, Shaun Friel, said the rise from 2017-18 was partly a reflection of greater awareness leading to more children getting in contact, but also a result of abusers increasingly using the internet to target victims.

“I wouldn’t want to present a picture that it [the internet] is a dangerous world but it just means that children can be contacted in ways they couldn’t before,” said Friel. “There’s great potential for children to be exploited through some of the mediums where young people spend their time.”

In more than a third (38%) of counselling sessions relating to child sexual exploitation (CSE), victims said they were targeted online, mostly through social media or video games, according to Childline’s annual review, published on Friday.

Most commonly, children sought help because they were forced to perform or watch sexual acts or had been persuaded to send naked images or videos of themselves. In some cases they were threatened that images would be shared with friends and family. Some victims turned to self-harm, alcohol or substance abuse as a way of coping.

A 14-year-old boy said he was badly affected by the death of his mother when younger. “I dropped out of school, lost a lot of friends and was very lonely. I spent a lot of time online gaming and I can’t remember how, but I started talking to this guy. We talked quite a bit for a long time and eventually met up. We met in a flat and I assumed we would watch movies or something.

“As soon as I got there he started kissing me and asking me to massage him. I didn’t really know what was going on. He then performed oral sex on me which I really didn’t like. Once he finished he told me to leave. I feel so used and stupid for even meeting him.”

An 18-year-old girl who was abused when younger said she also went online because she was lonely and ended up sending naked pictures and videos to older men she was chatting to. “I got compliments and didn’t know how to say no,” she said. “Most of them knew I was just 13 and some of them threatened to post the pictures online if I didn’t send more. I feel sick just thinking about it and feel so insecure about all this coming back to haunt me.”

Compulsory lessons in relationships (primary and secondary schools) and sex education (secondary only) begin from September next year. But Childline says teachers must be provided with proper training to ensure the lessons are effective and relevant.

The Childline founder Esther Rantzen, who highlighted the increasing prevalence of sexting, said: “Victims feel trapped because of an overwhelming sense of shame and humiliation. They think they will be blamed but often they are tricked by people they believe to be genuinely in love with them. Teachers can play their part, and so can families.”