York Crown Court heard how he saw the girl playing in a field off Melrosegate, York, and took her behind a row of nearby shops where he knew there was a secluded area of wasteland.

He then pulled out a knife, pushed her into long grass and told her to remove her underwear, which she did.

But when the girl repeatedly said she wanted to go home to see her mum and dad he eventually let her free without further incident.

Judge Wolstenholme told Bargh that he was a danger to the public and he must serve life imprisonment and would not be released until it was considered safe to do so. He said: “As long as you are considered to be a danger to the public you must remain in prison. If and when you are released you will remain on licence subject to conditions for the rest of your life.”

The judge said: “You have previous convictions and have served four years imprisonment for a very similar offence where you went on to indecently assault a little girl.

“You have been released early, but you were later convicted of harassment where you were following some other young girls, no doubt with a sexual motive.

“It’s clear to me that you represent a very serious threat to the public, particularly young girls.”

David Bradshaw, prosecuting, said Bargh had previously been convicted in 1997 of indecently assaulting a young girl in a toilet cubicle at a York primary school. He forced the girl to remove her trousers, but she was rescued by the headmaster of the school before anything else could happen. Bargh was 19 when that happened.

He has since been convicted of sex acts in public and following papergirls on their rounds and photographing them.

Mr Bradshaw said Bargh was captured on a nearby shop CCTV as he led the girl away.