Grooming gangs that preyed on 700 girls and vulnerable young women in the North East carried out their abuse with “arrogant persistence” before a major operation was launched to stop them, a Serious Case Review has found.

A 150-page report has been published into the authorities’ response to child sexual exploitation (CSE) in Newcastle, following a series of trials which saw 22 defendants sentenced for a range of offences including rape, drugs and prostitution.

Efforts to find out why the perpetrators thought they could abuse vulnerable women and girls have been rebuffed, with only one defendant agreeing to help the inquiry, and he denied guilt, blaming a government cover up.

The Serious Case Review found things have improved since 2014 and that in Newcastle there was no reluctance to start an investigation into grooming due to political correctness or fears of being branded racist – a factor in previous abuse scandals elsewhere.

But before 2014, the report stated that perpetrators were not consistently investigated and so went unpunished.

The report said: “This sent an unhelpful message to perpetrators – they were unlikely to be prosecuted or prevented from continuing to abuse – encouraging an arrogant persistence.

“It also had a significant impact on victims who learnt that nothing would be done against perpetrators.”

That changed after Northumbria Police launched Operation Sanctuary.

According to the review, the abusers were mainly “not white but came from a diverse range of backgrounds including Pakistani, Bangladeshi, Indian, Iranian, Iraqi, Kurdish, Turkish, Albanian and Eastern European”.

A total of 22 young women gave evidence at the trials which resulted in substantial prison sentences.

But the review estimated there were around 700 victims in total in the Northumbria Police force area, 108 of whom were from Newcastle.

The only abuser to help the inquiry was an asylum seeker who had spent 10 years in Turkey, around five in Greece and some time in Italy and France and hoped to get to Canada.

He exploited a 15-year-old girl and later showed no regret, telling the inquiry team he was only convicted “because of a conspiracy by the government, police and the judge who paid the victims”.

The report continued: “If convicted for rape in his home country, he would be beheaded or buried up to the neck and stoned.

“He was asked about what he thought about the United Kingdom and influences in his education.

“He said you can get anything here – any sex, drugs, alcohol. There is no control.

“He spoke in a derogatory way about lack of morals in British girls and did not go with Muslim girls because there are not many of them.”

The report said it was “unfortunate” there was not more input from other perpetrators.

Operation Sanctuary was launched in January 2014, a month after a young woman with learning difficulties told her social worker she had been sexually abused.

The authorities stepped up their response when they realised the problem was far worse than previously imagined.

Barrister and CSE expert David Spicer who led the review, said other towns and cities could learn from Newcastle’s response.

He said: “Unlike some other areas, Newcastle agencies did not try and sweep this under the carpet but actively went looking for it – and as a result, a large number of perpetrators were arrested and prosecuted, and victims saved from further trauma.

“That is not say that lessons have not been learned.”

Northumbria Police paid an informant £10,000 for information about the groomers and it later emerged he was a convicted child rapist.

The review said this was not an issue within its scope, but added: “During conversations with some victims, they expressed concern that this informant may have abused them and they were reassured there was no evidence of this.”

The review was carried out for Newcastle Safeguarding Children Board and Newcastle Safeguarding Adults Board.