A man groomed online and sexually abused by a string of older men when he was 13 has been denied compensation because the agency that handles claims says he “consented” to the assaults.

Peter, who is now 19, was abused by 21 men, two of them teachers, who all acted independently. They were found guilty of charges including sexual activity with a child, causing or inciting a child to engage in sexual activity, and meeting a child after sexual grooming.

A judge who presided over most of the cases made it clear that Peter was not to blame, describing the actions of one perpetrator as vile and depraved.

But the Criminal Injuries Compensation Authority, the government agency that makes financial awards to victims of violent crime, has refused Peter compensation on the grounds that he “willingly” met the men after registering on websites for over 18s, had not been manipulated and “consented in fact” to the sexual contact. Human rights organisation Liberty is appealing the ruling.

Peter (not his real name), who needed psychiatric help for five years following the abuse, told the Guardian he was shocked and distressed by CICA’s decision.

“I was a child being manipulated and used. After years of people telling me the men were in the wrong and I was a victim, having a government-linked agency telling me it was all consensual was very, very upsetting,” he said.

“I can’t believe we’re actually having to fight them on this. I felt like they were saying, ‘you did this to yourself, so why should we help you?’”