Keelan Rowley, 20, from Ruaton Drive in Clacton, used social media sites such as Instagram and Snapchat to target 14 girls, including four who were just 12 years old.

Chelmsford Crown Court heard how during 2015, Rowley targeted schoolgirls, all of whom lived in the Hertfordshire area and demanded that they send nude photographs or videos of themselves.

Rowley told the girls that if they did not do what he asked then he would subject them to sexual violence or share intimate pictures of them with their friends or family.

Rowley soon came to the attention of Hertfordshire Police and when his address was traced to Clacton the investigation was passed to Essex Police’s specialist POLIT (Police Online Investigation) Team.

The investigation showed that Rowley had targeted four 12-year-olds, two 13 year-olds, two girls aged 14, one aged 15 and three aged 16.

One girl refused to co-operate with police.

The court heard how two of the terrified victims complied with Rowley’s demands and he posted images and footage of them on social media.

The POLIT team executed a warrant at Rowley’s home in November 2015 and he was arrested.

Rowley was charged and on March 13 at Chelmsford Crown Court, he pleaded guilty to:

Two counts of inciting a child under the age of 13 to engage in sexual activity;

Five counts of inciting sexual exploitation of a child aged between 13 and 17;

Five counts of inciting a child aged between 13 and 17 to engage in sexual activity;

Two counts of making an indecent image of a child and;

One count of distributing an indecent image of a child.

Rowley was jailed for 64 months, put on the Sex Offenders Register for life and was made the subject of a 10 year Sexual Harm Prevention Order.

Following the sentencing, investigating officer DC Suzanne O’Neill of Essex Police’s POLIT team, said: “Rowley was a cold and calculated sexual predator.

“He used social media to target young girls and blackmailed and exploited them to comply with his demands. Two of them were so terrified they did everything he asked.

“However these girls have shown nothing but bravery and courage and have worked with us to make sure Rowley is put behind bars where he belongs.

“We know offenders like Rowley use social media to sexually exploit young people and that’s why we urge people to know how to keep themselves and their loved ones safe online.”