It also warns that one in four child sexual abuse victims don’t report offences because they think police will be unsupportive.
The findings were part of a six-month inquiry by the All Party Parliamentary Group (APPG) on Adult Survivors of Childhood Sexual Abuse, chaired by Rotherham MP Sarah Champion.
The report exposes, through research published for the first time today, an alarming drop in the use of pre-charge bail since reforms in the Policing and Crime Act 2017.
In the year after the Act became law, the number of people suspected of a sexual offence against a child released with pre-charge bail conditions fell by 56 per cent, while the number of suspects released under investigation by police increased by 1,047 per cent.
Across the 20 out of 43 police constabularies that provided information, 2,993 suspected child sexual offenders were released without conditions in 2017/2018.
Ms Champion said: "I am particularly concerned that the Government bail changes in 2017 means a massive increase in suspected perpetrators are being released without any bail conditions before they are formally charged. This presents a huge risk to survivors, witnesses and the public and the Government has to act to address this safety risk immediately."
Nearly 400 survivors of child sex abuse took part in the inquiry, which campaigners say has uncovered a "total lack of faith in the criminal justice system", with just 54 per cent having reported their abuse to police.
Of those who reported their abuse, 64 per cent did not see a charge brought, 77 per cent said the communication of this information was poor or very poor and nine out of 10 said the support provided to them was poor or very poor.
One survivor said: “I called the police myself. They never called me. I had to explain myself in detail to three different officers, over four different phone calls. The third police force called me by the name of another victim. Incredibly careless"
Survivors also expressed confusion at the role of the CPS, not least as frustrated police often end up delivering decisions made on their behalf.
Ms Champion said: “Our inquiry found overwhelming evidence of persistent failure by the police and CPS to support and secure justice for adult survivors of childhood sexual abuse.
"Survivors of child sexual abuse are losing faith in the criminal justice system. They don’t feel listened to or respected by the police or CPS, they’re not given updates about their case and too often they’re treated insensitively.
"To me it just feels very callous and a complete lack of awareness and sympathy by the police."
Chief Constable Simon Bailey, the National Police Chiefs' Council lead for child protection said policing had made mistakes in the past but lessons had been learnt.
He said: "The approach today is very different, which is reflected in increased confidence in victims and survivors coming forward to tell their story.“There’s currently insufficient evidence to judge whether the decrease in use of bail puts vulnerable victims at greater risk but we want to minimise that potential and so have recently published operational guidance on the use of bail and release under investigation.“This guidance clearly tells officers that bail is a legitimate tool and it should be used to protect victims or vulnerable people when necessary and proportionate.”
The report makes several recommendations to the Government, which include introducing a victim's law to strengthen survivors’ rights and amending bail legislation so that suspects under investigation for child sexual abuse will only be released from police custody on bail.
Ms Champion said: "The inquiry has made practical recommendations to the Government on how to restore survivors faith in the police and justice system.
"Unless addressed, the current situation risks survivors making the decision not to report abuse; meaning child sexual offenders go unpunished and pose a risk to more children.
"The Government has to rebuild survivors’ confidence in the system as a national priority."
A Government spokesman said: “We welcome the fact that more victims of child sexual abuse and exploitation are coming forward to report abuse and get the support they need.
“Police forces continue to improve their response to these crimes, but we know there is more to be done, which is why all Chief Constables have committed to a policing action plan that aims to raise the standards in tackling child sexual abuse to ensure a consistently strong approach.
“The Government’s Victims Strategy sets out how we will improve the support offered at every stage of the justice system, and we have nearly doubled the funding for victim support services since 2013.”