Image caption Amanda Spencer was sentenced after being convicted last week of 16 child prostitution charges

A woman who ran a child sex ring from the age of 16 by luring "weak and vulnerable" girls into prostitution has been jailed for 12 years.

Amanda Spencer, from Sheffield, initially befriended her victims - some as young as 13 - before forcing them to have sex for cash.

She spent the money on drugs and alcohol, Sheffield Crown Court heard.

Spencer, now 23, was convicted last week of 16 charges relating to child prostitution.

She was cleared of seven other charges, including arranging or facilitating child prostitution, intentionally causing or inciting a person to become a prostitute, and one count of trafficking within the UK for sexual exploitation.

During a trial lasting more than two months, the jury heard Spencer deliberately targeted vulnerable girls in Sheffield.

Co-defendant jailed

Prosecutors decided they would not pursue a retrial on a further 14 charges on which the jury could not reach a verdict.

Spencer denied all the crimes of which she was accused, claiming her victims had either made up their accounts or that she had never met them.

She had been on trial with four men, who were also accused of offences involving young girls.

Three were acquitted last week but 68-year-old Ian Foster was convicted.

Image caption Ian Foster, who was on trial alongside Amanda Spencer, was jailed for 14 years

Foster, from High Green, was jailed for 14 years after he was found guilty of three counts of sexual assault.

He had previously been found guilty of 12 child sex offences, at a separate trial in February.

Jurors heard Foster bought his victims - some as young as 12 - alcohol and cigarettes and took them to nightclubs before abusing them at his home.

After the sentencing, South Yorkshire Police said the convictions followed "a lengthy and complex inquiry by the force spanning more than two years, exploring the exploitation and sexual abuse of young girls and young women between 2004 and 2011."

Officers became increasingly concerned for the welfare of young girls who were repeatedly going missing and launched an investigation in 2011.

'Threaten violence'

"Intelligence experts began mapping their movements to establish if there was a pattern and Spencer quickly emerged as the common denominator in their disappearance, prompting officers to make contact with the girls and uncover the illicit crimes," a spokesman said.

"Gradually some of the girls revealed what had happened to them, how Spencer had befriended them, gained their trust and then abused it in the most shocking way by using threats and violence to coerce them into engaging in prostitution and having sex with different men."

Det Ch Insp Bob Chapman, who led the investigation, said Spencer had carried out "sustained and calculated abuse".

"Amanda Spencer preyed on some of the most vulnerable people in our community, grooming them under the pretence of friendship, using the lure of drink and drugs in order to coerce them into doing what she wanted and when her demands weren't met she would threaten violence, intimidating them into submission," he said.

"In return for providing young girls to a number of men, Spencer too was given alcohol, drugs and money. As the court has heard, she was the facilitator and most definitely the person who was pivotal to sustaining the abuse these girls experienced."