A SERIAL sex offender who preyed on a schoolgirl online is facing an extended prison term to protect the public.

Stephen Jardine will be assessed for "dangerousness" by a probation officer before he is sentenced in several months.

Jardine asked the teenager for indecent photographs of herself after befriending her on the social media site Instagram.

The 28-year-old was on a suspended jail sentence and the subject of strict prohibitions after earlier convictions.

Jardine, of Pacific Drive, Thornaby, near Stockton, pleaded guilty to a catalogue of offences at Teesside Crown Court.

Prosecutor Richard Bennett said: "The case needs to go off for a pre-sentence report to consider dangerousness.

"It is a long prison sentence on any view, but I was concerned the defendant might want to learn his fate as soon as possible.

Jardine admitted two charges of causing or inciting a child to engage in sexual activity, and one attempt to.

He also pleaded guilty to two counts of breaching a Sexual Harm Prevention Order imposed by magistrates last year.

The court heard he used the name Ash18 on social media, which amounted to a failure to comply with the order.

He also admitted three charges of making indecent images of children - a total of almost 1,500 - before his arrest last month.

The court was told Jardine had been involved in a number of other conversations with other children on Instagram and is suspected of asking them for indecent pictures.

Police are trying to trace the girls, but because the site is owned by Facebook - a non-European company - the requests are taking time, said Mr Bennett.

The victim who is the subject of the charges Jardine has admitted, went to police in West Yorkshire last November, but they only got details to pass to their Cleveland counterparts in May.

Mr Bennett said: "The new matters, when they come to be investigated properly, don't appear to be contested because he has made admissions.

"From the Instagram messages, there also appears to be a suggestion that he had been exchanging images of children with another adult."

Andrew Turton, defending, said: "We could order a report and come back for sentencing, and by that stage there would be a determination of risk assessment and dangerousness in the report."