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The Criminal Injuries Compensation Authority is to be investigated over concerns it is failing child sex abuse victims, the Victims' Commissioner has told 5 live Investigates.
Hundreds of people have been refused payouts since 2012, charities claim, many because they are deemed to have consented to abuse.
Barnardo's and Victim Support said it was "devastating" vulnerable people.
The government said all victims should get the compensation they deserve.
The Ministry of Justice estimates around 30 cases a year have been refused compensation on consent grounds.
Figures from the Criminal Injuries Compensation Authority (CICA), seen by the BBC, also show 180 child sex abuse victims have been refused compensation since 2015 because they lived with a family member who abused them.
Under CICA guidelines, victims who lived with their abuser before 1 October 1979 are not entitled to compensation. The rule was initially introduced to prevent abusers benefiting from payments to victims they were related to.
Alissa Moore and her younger sister were both raped by their father. He was given a 24-year sentence in 2015.
But although Alissa's sister was awarded compensation, Alissa has been refused a CICA pay-out because she was abused before October 1979.
"The justice system put him in prison. They thought that what he did to us was worth 24 years' of prison - but CICA don't accept that I was abused," she said.
"It was OK for him to abuse me - but it wasn't OK for him to abuse my sister.
"I feel really angry. Why should victims be made to feel that way when they've already suffered?"Image copyright Victims' Commissioner Image caption Baroness Newlove, Victims' Commissioner for England and Wales, said compensation had a "critical role" to play in helping victims of serious crime recover
Human rights charity Liberty has appealed against a CICA decision, made in November 2015, to deny a 13-year-old boy compensation on the grounds he consented to his abuse. The appeal will be heard next month.
Twenty-one men were convicted on a range of sexual exploitation crimes against him.
In July, the government promised an "urgent" review of cases where the CICA had rejected claims in cases where victims were deemed to have consented.
But charities Barnardo's and Victim Support said they are still waiting for the government to deliver on its pledge.
"The delay in reviewing these cases means vulnerable young victims are potentially being refused compensation and left devastated at being told they were effectively to blame for their own abuse," they said.
"Any child that suffers sexual abuse is a victim. This issue has dragged on for long enough."
It is illegal to have sexual activity with anyone under 16 but CICA does not automatically make payments to all victims.
The charities have called for the rules to be changed so "no child groomed and manipulated into sexual abuse is denied compensation because they complied with their abuse through fear, lack of understanding, or being brainwashed into believing their abuser loved them".Image copyright Getty Images
Baroness Newlove, Victims' Commissioner for England and Wales, said compensation had a "critical role" to play in helping victims of serious crime recover.
Her investigation, which will begin in early 2018, will look at how well the CICA works "for vulnerable victims."
Sarah Champion, Labour MP for Rotherham and former shadow minister for preventing abuse, welcomed the announcement, but said there needed to be a whole scale review of the CICA.
She told BBC 5 live Investigates: "All the secrecy needs to stop; this is public money being spent to acknowledge the suffering of victims of crime, not a way for civil servants to compound injustice."
An MoJ spokesperson said: "We are absolutely clear [that] victims who have been groomed should never be treated as if they consented.
"We want to make sure every victim gets the compensation they deserve. That's why CICA are reviewing their staff guidance to ensure that every instance where grooming could be a factor is identified.
"CICA are also actively engaging victim support groups and relevant charities with specialist knowledge in this area to make sure the revised guidance is as robust as it possibly can be."
You can hear 5 live Investigates at 11am on Sunday, October 1 on BBC Radio 5 live