People in some parts of England and Wales will soon be able to find out from police if their partners have a history of domestic violence.
The Home Office has announced year-long trials giving police the "right to ask" for information in Greater Manchester, Nottinghamshire, Wiltshire and Gwent.
The scheme is dubbed Clare's Law, after a woman murdered by a former partner.
But domestic violence campaign group Refuge has attacked the scheme, saying it will do little to protect victims.
Clare Wood, from Salford, Greater Manchester, was murdered in 2009 by a former boyfriend with a violent background.
The 36-year-old mother had made several complaints to the police about George Appleton, whom she had met on the internet, before he killed her. He was later found hanged.
The Independent Police Complaints Commission criticised Greater Manchester Police for failings in the case.
Since her death, Miss Wood's father, Michael Brown, has campaigned for people to have greater rights to know about the violent past of partners.
Following a consultation, ministers have backed an arrangement similar to parents' right to ask whether someone who has access to their children has a history of sex offending.
The Home Office has not yet disclosed how the scheme will work.
Police already have common law powers to provide information about someone's background if officers think there is a pressing need to do so to prevent a crime.
Home Secretary Theresa May said it was designed to "prevent tragic incidents" and the Association of Chief Police Officers said it was "fully supportive" of the move.
Miss Wood's father welcomed the pilot scheme and said that, had it been in place earlier, it would have given his daughter the chance to make an "educated decision" about her relationship with Appleton.
History of violence
"I believe that if my daughter had known of the past of her partner she would have dropped him like a hot brick and scampered out of there," Mr Brown told BBC Radio 4's Today programme.
Home Office statistics suggest two women are killed by their current or former partner each week in England and Wales.
T, from Wolverhampton, contacted the BBC to say she wished she had known that her husband had a history of violence.
"I was badly treated by my husband and beaten often," she said.
"The first time he did it he said he didn't know what he had done and it wasn't in his nature to do this. I accepted this, but was then beaten again and more frequently. If I had known that he had a history of violence then I would have left much sooner."
S, from Lincolnshire, was in an abusive marriage for 12 years but was unaware her husband had been arrested for beating a former girlfriend.
"If I was a single woman, and especially if I had children, I would definitely want to have access to a register that recorded details of abusers before contemplating a serious relationship," she said.
But Sandra Horley, chief executive of Refuge, said: "Why are we spending money on untested, untried, costly initiatives?
"The reality is that most of the perpetrators aren't known to the police - and women may not even take up this scheme.
"The government's own assessment of this new scheme is that, at best, it will reduce domestic violence by half a percent."
She said the Home Office should instead tackle the issue by improving how police respond to calls for help.
But Equalities Minister Lynne Featherstone said the scheme was "one part of a methodology to try and deal with domestic violence which is unacceptable and epidemic in this country".
The child sex offender disclosure scheme, Sarah's Law, which is the basis for the proposed Clare's Law, is now in place across all police forces in England and Wales.
It was the result of a long-running campaign by Sara Payne, whose daughter Sarah was murdered by a known paedophile.
During the scheme's pilot in four police areas, 315 applications were made which uncovered 21 cases where a potentially dangerous person did have access to an applicant's child.
Clare's Law trials will begin this summer.
Home secretary Mrs May said: "The government is committed to ensuring that the police and other agencies have the tools necessary to tackle domestic violence to bring offenders to justice and ensure victims have the support they need to rebuild their lives."