The Betrayed Girls – BBC 1 at 8.30 pm tonight

After BBC’s explosive drama Three Girls aired in May, a new documentary from the broadcaster investigates how the teenage victims  of the Rochdale grooming gangs were failed so badly by authorities.

With testimonies from victims and those at the heart of the case, the feature-length programme makes for uncomfortable but vital viewing.

The testimony of sexual health worker Sara Rowbotham, who was a first point of contact for many of the young victims, is particularly rage-inducing.

She tells how her warnings were ignored by police and social services on over 180 separate occasions, so persistently that she believed a girl would have to die before the police took notice.

A girl did die – 13-year-old Victoria Agoglia, who passed away in 2003 from a suspected drugs overdose.

The documentary claims a letter that the teenager wrote detailing how she was plied with drugs and alcohol before being raped was given to the police in 2003, kick-starting Maggie Oliver’s involvement. But nothing came of it, Agoglia died just months later and the case was dropped in 2005.

Footage shown of the BBC News report announcing Agoglia’s death features hallmarks of government organisations hurrying to absolve themselves from responsibility.

But most harrowing are the statements of the victims, voiced by actors, which describe what it’s like to be a vulnerable, almost invisible young girl who thinks she’s found friends, only to be abused first by the rapist and then again by a faulty system.