A SEX offender who used a false name to contact underage girls and send them sexually-charged messages left one teenager feeling “disgusted and used.”

Joe McCallum, 32, contacted six teenage girls in the Colchester and Maldon areas, using aliases to avoid detection.

Police became aware of his activity after a vulnerable teenage girl went missing in March last year.

She was later found, but it became apparent she had got into a vehicle with McCallum, who had given her money and offered to buy her a coat.

McCallum, who in 2014 was convicted of making indecent images of children and causing a child to engage in sexual activity, was stopped by officers and his phone was checked.

In breach of a sexual harm prevention order, he was found to have downloaded and used the social media app Snapchat before deleting it.

He had also been using the dating app Tinder without permission and had failed to register a mobile phone with the police.

When further investigation of his phone was carried out, police found he had sent inappropriate messages to five other children.

Chelmsford Crown Court heard he used false names on each occasion to avoid detection.

He invited one young girl to a party and told her “she best be worth the cab money.”

To another girl, he sent requests for naked photographs and even offered to pay for the pictures.

The court heard one girl felt “disgusted and used”, while another feared McCallum may approach her if he knew what she looked like.

Judge Walker deemed McCallum to be a dangerous offender.

Of one victim, he said: “Her mother understandably was frightened as a result of your communications.”

McCallum, of HM Prison Chelmsford, previously of Destination Drive, Colchester, admitted six breaches of a sexual harm prevention order, four counts of failing to comply with notification requirements and three counts of sexual communication with a child.

He was sentenced to five years imprisonment and will remain on the sex offender’s register for life.