Forensic experts are to review 4,000 more unsolved sex crimes as part of a £1m "cold case" project, the Government has announced.
Advances in DNA technology will be used to re-analyse evidence from rape and serious sex offence cases dating back to 1991.
The DNA profiles obtained will be compared against the National DNA Database for possible matches.
More than 11,000 cold cases have been reviewed by the Forensic Science Service since 2004, resulting in 30 convictions.
The Home Office said almost all the offenders convicted so far were "persistent and prolific violent criminals" with crimes stretching back years.
Home Office minister Tony McNulty said: "Their removal from our communities has undoubtedly had a significant impact on community safety."
He added: "Our message to perpetrators is clear - these cases are never closed by the police.
"We are determined to ensure that victims receive the justice they deserve and will continue to use advances in technology to help solve crimes, convict offenders and bring closure and relief to people who have had to live with the terrible effects of these crimes over many years."
The Government has committed £350,000 to the latest stage of the project, known as Operation Advance.
