A child sex offender who lured a string of girls as young as 15 into his flat to give them tattoos before sexually assaulting them has been told he is facing a lengthy jail term.

Paul McLellan, 43, was told by a sheriff it was "perfectly clear" he was "grooming some of these girls with a view to further sexual activity".

McLellan was convicted after a three-week trial of a total of 22 charges - 12 of illegally giving tattoos to girls under the age of 18 and 10 sexual offences.

One of McLellan's victims told the trial she had met him through Facebook, the internet social networking site, after posting a message asking if "anyone did tattoos".

She went to his house, where McLellan groped her as he wrapped the freshly inked tattoo in cling film.

Other girls were subjected to degrading ordeals in which McLellan grabbed them and made them touch him. He also touched them intimately.

On one occasion he exposed himself, grabbed the girl - who was 15 at the time - "with intent to rape her".

After a jury at Dundee Sheriff Court gave its verdict after five hours of deliberation, the court was told McLellan had previously been jailed for three years in 2003 in England for two sexual assaults on young girls.

Then, in 2006, he was jailed for four years for sexual offences against girls under the age of 16 in Scotland.

The court heard McLellan, whose address was given as c/o Perth Prison, had been released from another jail term only two months before he started his campaign of tattooing and sex attacks.

He was also on licence from his 2006 sentence at the time of the offences.

Fiscal depute Douglas Wiseman told the court that as part of his licence conditions McLellan was banned from approaching or contacting people under the age of 17 in any way, shape or form.

Sheriff George Way deferred sentence until next month for social work background reports and a psychiatric assessment.

He said: "It is perfectly clear from all I have heard that you are a person who is a considerable danger to young girls.

"I have no doubt you were grooming some of those girls with a view to further sexual activity.

"I doubt my sentencing powers are adequate and I may have no choice but to remit you to the High Court for sentencing."

McLellan showed no emotion as he was handcuffed and led to the cells.