An independent review published by Salford Safeguarding Board said it was "difficult to think of a more vulnerable child".
The girl, who is deaf and cannot speak, was trafficked from Pakistan aged ten.
Her plight was only detected when she was found by trading standards' officers investigating a scam.
Ilyas Ashar was jailed for raping the girl, benefits fraud and trafficking, and his wife Tallat was jailed for benefits fraud and trafficking.
The pair succeeded in "in maintaining a cruel deception," the report notes.
The 76-page report said none of the various agencies protected the girl, who worked as a servant, when they came into contact with her.
It stated: "For a country with a reputation as a safe place in which human rights are upheld and with sophisticated arrangements for safeguarding children and vulnerable adults, this was indeed a shaming failing."
It highlighted key failures by official agencies:
It said there was a series of missed opportunities by different authorities.
The girl arrived from Pakistan on a forged passport which put her at twice her actual age.
She never had an interpreter when she was seen by different officials.
The girl had an employment contract with the couple ensuring she would neither have sex nor be locked indoors against her will, which could "have suggested she was vulnerable", said the report.
NHS staff were "too inhibited" about race issues to question the family.
The couple were originally sentenced at Manchester Crown Court in October 2013, but had their sentences increased in February last year, with Ilyas Ashar's extended from 13 years to 15 and Tallat Ashar's sentence raised from five to six years.
Social services said the girl, now in her 20s, had made a "remarkable recovery".
A girl who was kept in a cellar and repeatedly raped was the victim of a "shaming failing" by those who should have protected her, a report has said.