Previous legal guidance has meant offenders who murdered a victim while on bail for rape would be prosecuted for only the murder, because the resulting sentence would be expected to be sufficiently high to cover both offences.
Today, Keir Starmer QC, the Director of Public Prosecutions has announced new guidance, meaning they should now be charged with rape as well.
The change is a victory for a campaign by John and Penny Clough, whose daughter Jane, 26, was stabbed 71 times by her ex-partner Jonathan Vass in July 2010 while he was awaiting trial for repeatedly raping her.
Vass was jailed for life in October 2010 after admitting the murder, but the rape charges were left on file.
In future cases, rape charges that are linked to murders will no longer be left on file but will be prosecuted except in the most "exceptional circumstances", Keir Starmer has said.
He told the BBC's Today Programme: "The point made by Mr and Mrs Clough and others in a similar situation is that although the overall length of sentence is one factor, it's not the only factor.
"They feel very strongly that justice requires the perpetrator to be judged for the rape as well as the murder.
"It's a very powerful argument they have put forward and in the face of that argument we have changed our approach.
He added the change would apply to the offence of rape only.
Mr Starmer explained that leaving rape charged on file was neither an acquittal nor a conviction.
He said: "Jane's parents felt that this was wrong. She had wanted Vass tried for rape and her murder effectively denied her justice."
Writing in the Times newspaper to outline his revised guidance, Mr Starmer said: "In cases where an offence as serious as rape is alleged in the context of a subsequent murder, the Crown Prosecution Service should persist with the rape charges save in exceptional circumstances, even if no extra penalty can realistically be imposed.
"Although the CPS does not act on behalf of victims or their families, it is vital that we acknowledge how important it is that families feel that justice has been done.
"In this new guidance I have made it clear that prosecutors must consult families whenever a plea or conviction for murder is entered and explain to them the implications of not proceeding with other charges.
"That does not mean that the CPS will always persist with charges, but leaving charges to lie on the file will now be the exception, not the rule."
Mr Clough, 51, a railway engineer, told the newspaper he and his wife had wanted Vass tried for the rapes so that he would be treated as a sexual offender and consequently placed on the sex offenders register.
"So far as we are concerned, he is not being treated as a sexual offender. But the fact is that Jane paid for the right to have those charges with her life," he said.
Mr Clough said the change would go "some way to making us think that Jane's death has made a difference".
