Keir Starmer says new child abuse trial guidelines are 'biggest shift for generation'
Final guidance on the prosecution of cases involving child sexual abuse in England and Wales has been published.
Director of Public Prosecutions Keir Starmer said it represented the biggest shift in attitude across the criminal justice system "for a generation".
Under the guidelines, prosecutors are told to focus on the credibility of allegations, not on whether victims make good witnesses.
All suspects will also be investigated to see if they possess indecent images.
The guidelines cover how victims should be treated and how a case should be built and presented in court.
The BBC's legal correspondent Clive Coleman said it was "something of a watershed moment".
Victims have previously been disbelieved or discouraged, he said, but the new guidelines represented a move towards a "more sophisticated knowledge of psychology".
A list of "myths and stereotypes" about behaviour previously thought to negatively impact the credibility of young victims has also been included, so the use of such preconceptions can be challenged in court by prosecutors.
The list includes inconsistencies in what the victim remembers and whether they were drunk or wearing revealing clothes.
A joint protocol for information sharing in child sexual abuse cases has also been published alongside the guidelines, in which police and prosecutors are expected to share information with social services, schools and family courts.
The publishing of the final guidelines follows a three-month public consultation and takes immediate effect. The information for joint protocol will come into force in England and Wales on 1 January 2014.
Changes were sought after there were complaints that too many cases had been dropped before trial because of fears that the allegations would not stand up to scrutiny.
One of the most serious recent prosecutions of sex abuse and street grooming - in which 10 men were convicted - was initially shelved because of doubts over the credibility of the victims as witnesses.
TV and radio presenter Jimmy Savile was not prosecuted when he was alive and, more recently, a row erupted after a prosecutor called a 13-year-old victim "predatory".
Mr Starmer said: "For too long, child sexual abuse cases have been plagued by myths about how 'real' victims behave which simply do not withstand scrutiny.
"The days of the model victim are over. From now on these cases will be investigated and prosecuted differently, whatever the vulnerabilities of the victim."
Mr Starmer said that because the guidelines were the result of discussions with judges, the police, experts, victims' representatives and the government, they would "stand the test of time".
He said that because "possession of indecent images of children has been found to be a common feature" of child sexual abuse cases the police would now investigate it in every case of child sexual abuse.
The guidelines will also highlight a number of ways victims of abuse can be manipulated and blackmailed to keep quiet, which include threats to publish indecent images or implicating victims in other offences.
They also seek to raise awareness of how victims in some ethnic communities are controlled by offenders who might use notions of "honour" or "shame" to deter them.
Shadow attorney general Emily Thornberry said it was not clear how much of the guidance would actually get used in practice.
"These proposals are a welcome effort to correct the over-cautious stance the CPS took in the Jimmy Savile and street-grooming cases," she said.
"However, the guidance contains a lot more 'shoulds' than 'musts' which makes it far from certain how much of this will actually get implemented."
The NSPCC's Alan Wardle said the changes "will start to make a positive difference for child sex abuse prosecutions which in the past have been dogged by difficulties".
The Deputy Children's Commissioner for England, Sue Berelowitz, said the CPS had "worked hard to improve the experiences of child witnesses and increase the likelihood of securing convictions by ensuring that judges and juries better understand the psychological and emotional impact on victims of their appalling experiences".
The Chief Executive of the Survivors Trust, Fay Maxted, welcomed the new approach. She told BBC Radio 5 Live: "It is at least now saying that we need to stop focusing on questioning whether the victim is telling the truth and actually look at what they're saying has happened and investigate that."