A murdered woman's mother has said she is "relieved" a bill denying parole to killers who refuse to disclose a body's location has cleared the Commons.
The Prisoners (Disclosure of Information About Victims) Bill was passed unopposed by MPs.
The legislation is dubbed Helen's Law after Helen McCourt, whose killer Ian Simms was freed from jail without disclosing the location of her remains.
Marie McCourt said the law may be too late to help her find Helen.
"I'm relieved it has got through at last," said Mrs McCourt who has campaigned for the change since Simms' conviction.
"It should have been made law twice before, but elections were called before it could get through Parliament. I hope it means other mothers will not have to suffer like me."
The bill will also apply to offenders who do not reveal the identity of child abuse victims pictured in illegal images.
The legislation places a statutory obligation on the Parole Board to take into account an offender's non-disclosure of certain information when making a decision about their release from prison.
It applies to prisoners serving a sentence for murder or manslaughter or for taking or making an indecent photograph of a child.
Justice Secretary Robert Buckland said: "To all those families affected by despicable crimes like these, I pay warm and heartfelt tribute.
"I hope that they will be able to take some comfort from knowing that their dedication provides some hope from other families affected by the cruel and heartless actions of those who refuse to disclose vital information."
Simms was jailed for life in 1989 after killing Helen as she walked home from work in Billinge, Merseyside, but was released in February.
The bill also responds to the case of Vanessa George, a nursery worker convicted in 2009 of multiple counts of sexual abuse, and taking and distributing indecent images of children at a Plymouth nursery. George refused to identify the victims.