A PROLIFIC sex offender who spent days hunting for child victims online gave a nine-year-old boy detailed instructions about how to sexually interfere with his three-year-old sibling.

A Crown Court judge who was told about 23-year-old Jonathon Fell's latest sickening crimes jailed him for 45 months.

The court heard that the pervert - who has lived in Carlisle and Workington and subjected to close monitoring because of previous sex offences - was caught thanks to the efforts of police and Probation Service staff who became suspicious after learning that Fell had a secret phone.

A senior police officer today said the case shows that sex offenders subject to community monitoring will be caught and brought to justice.

Gerard Rogerson, prosecuting, said the offences were discovered in February last year after a Probation officer who was interviewing Fell noticed a mobile phone was vibrating in his pocket.

"At first, he denied having a phone," said Mr Rogerson. "But it was then produced, he was confronted, and the phone was seized."

Police in Cumbria who examined the phone found thousands of incriminating messages.

Fell, of Lowther Street, Carlisle, was repeatedly visiting online chatrooms to search for children to groom. He admitted four counts of attempting to incite a child to engage in sexual activity; and four of trying to communicate sexually with a child.

In the most disturbing offence he instructed a nine-year-old to sexually interfere with a three-year-old.

He usually made sure the child was alone. When confronted, Fell denied wrongdoing but then told police: "I can't stop myself."

Jeff Smith, for Fell, said he was immature and suffered PTSD. Recorder Philip Grundy described Fell's offending as "persistent and alarming", saying he posed a very high risk.

Fell was being managed in the community by the Management of Sexual and Violent Offenders Unit, who worked with detectives from the Crime and Safeguarding Team to bring Fell before the court. Detective Chief Inspector Matt Scott said: “This sentence demonstrates that cases of this nature are taken very seriously. If offenders choose to breach orders they are subject to, they will be prosecuted and brought to justice."

The defendant, who previously lived at Wastwater Avenue, Workington, most recently he has lived at Lowther Street, Carlisle. He will be on the Sex Offenders' Register indefinitely.