Evil Ian Ogilvie, 50, from Motherwell in North Lanarkshire, was caged yesterday at the High Court in Edinburgh by judge Lord Pentland.
The court had earlier heard how the beast and his friend Allan Donnelly, 47, had preyed on the teenager for months - even filming their sick antics. Pervert Donnelly was handed a 10-and-a-half year sentence last December for his role.
Ogilvie was on the Sex Offenders Register at the time of the attacks - and was also the subject of a supposedly strict Sexual Offences Prevention Order order banning him from going near under 16s.
The pair were snared after a man allegedly asked to take part in the rape of the child contacted police.
The shocking tale emerged in August last year when the pair admitted at the High Court in Glasgow to a string of sex charges. Sentence had been deferred so the court could obtain reports about their characters.
At their earlier appearance, judge Lord Pentland warned the duo that they had both taken part in a "deeply horrifying level of depravity".
On Monday, defence advocate Brian McConnachie QC told the court there was little that he could say that would mitigate his client's behaviour.
Passing sentence, Lord Pentland said the most appropriate way to deal with Oglivie was to give him an order for lifelong restriction.
The order means that the parole board can only release an offender once they have detailed information that they pose no serious threat to committing more serious crime.