Victims of crime in South Yorkshire will be able to challenge decisions to drop prosecutions or to not charge suspects under new rules.
The move was announced by the director of public prosecutions, Kier Starmer.
The “victims’ right of review” covers any decision by the Crown Prosecution Service not to pursue a case.
Announcing the move, Mr Starmer said victims had been treated as ‘bystanders’ in the past.
He said the move could affect about 70,000 cases a year, but would not cover those dropped by the police.
Ministers and campaigners said it would improve the way the justice system dealt with victims.
Martin Goldman, chief crown prosecutor for Yorkshire and Humberside, said: “The victim’s right of review allows victims to request a second opinion where we have made a decision to not start, or to stop, a prosecution.
“It not only demonstrates how attitudes to victims have changed, it also clearly shows how the CPS has changed.
“These reviews will be an entirely fresh examination of all the evidence and circumstances of a case.
“We are an open, honest and accountable organisation which is not afraid to admit its mistakes and put them right.
“Any victim of crime, which includes bereaved family members or other representatives, can now ask the CPS to look again at a case following a decision not to charge, to discontinue proceedings or to offer no evidence.”
The new policy, which is in effect now, follows a 2011 Court of Appeal ruling which stated that ‘as a decision not to prosecute is in reality a final decision for a victim, there must be a right to seek review of such a decision’.
The ruling referred to the case of Christopher Killick, who was jailed for three-and-a-half years for violent sexual attacks on two people who, like him, had cerebral palsy.
Mr Starmer said: “Refusing to admit mistakes can seriously undermine public trust in the criminal justice system.”