“We always knew this would be a major inquiry but the scale of it, and the sheer number of victims who have come forward, has been a shock.”
Detectives who are investigating child sex abuse claims spoke of their shock after more than 500 potential victims were identified.
The huge scale of the allegations suggests an organised paedophile ring was operating in the 1970s and 1980s at Medomsley Detention Centre near Consett, County Durham.
Police announced in August they were starting a fresh investigation into abuse at the centre for young offenders, who were mostly convicted of minor crimes.
In 2003 a previous police investigation led to the conviction of Neville Husband, a prison officer at Medomsley.
Husband was sent to jail for eight years after being found guilty of abusing five youngsters.
The publicity surrounding the trial then led to others coming forward and Husband was subsequently jailed for a further two years for these attacks.
After being released from prison he died from natural causes in 2010.
Now Detective Superintendent Paul Goundry, leading a 70-strong team, said: “We always knew this would be a major inquiry but the scale of it, and the sheer number of victims who have come forward, has been a shock.”
Husband, who went on to become a church minister, was in charge of the kitchens at Medomsley and would single out youths for sexual abuse, particularly those who had been in care and did not have strong family ties.
His former colleague, Leslie Johnson, a storeman, was jailed for six years in 2005 for sexual offences. He has also since died.
Police originally believed the pair were operating alone, but that view has changed after speaking to many victims.
Mr Goundry said: “From the statements, there is growing evidence to suggest there was an organised paedophile ring operating in Medomsley.”
He said the experience of many of the victims, sent for detention for relatively petty crimes, had ruined the rest of their lives.
The inquiry team was also investigating physical abuse of young detainees.
Solicitor David Greenwood, who is representing a number of victims, has said the Government may face compensation pay-outs worth £12 million if the victims who have come forward make claims.
North West Durham MP, Pat Glass has called for an independent inquiry into historic abuse at youth detention centres.
The Labour politician raised the issue with Keith Vaz, chairman of the Home Affairs Committee.
She has said: “I suspect this will go much wider than Medomsley and, during this investigation, we need to look at all historic abuse in custody.”