A government pilot scheme launched on Monday aims to prevent women from being trapped in abusive relationships by allowing them to find out about their partner's past. But while some have claimed the scheme, dubbed 'Clare's Law', could have saved lives, others argue they are at a "loss" as to why the government has announced the plans.

Two pilots are running this year in four areas of the UK - Greater Manchester, Gwent, Nottinghamshire and Wiltshire. As home office minister Lynne Featherstone put it: "If a woman suspects or wants to know her partner's history, she has the right to ask the police, but also the right to know which is the police pro-actively knowing the history of someone, and going and informing that woman."

But Refuge says the law, named after 36-year-old mother of one Clare Wood, who was murdered by ex-boyfriend George Appleton, simplifies domestic violence. Not all women leave their violent partners, and the violence does not always stop once they have separated. Equally, not all known offenders are known to the police.

"In all my years of running refuges, I have never heard a woman say 'if only the police had told me they knew my partner was an abuser I would have left him'," Sandra Horley, the charity's CEO, said.

Horley says it is more likely Wood died at the hands of her ex-partner because the police had not responded to her 999 call begging for help, rather than because she was unaware of Appleton's violent past.

There is also concern about what the law will mean in practice.

Emma Carr, deputy director of the campaign group Big Brother Watch, said: "Are the police going to disclose arrests or mere suspicion, despite someone never being convicted?

"We have a legal system based upon guilt needing to be proven in court and this should not be a means of bypassing that."

But Maura Jackson, chief executive of domestic violence charity Advance says the law could help a woman who works with her charity, who believes the only way she will leave her current relationship is "in a box".

"I can think of one lady that we have supported for a number of months," she told The Huffington Post UK.

"She's still in the relationship, she still feels that the only way she's going to leave that relationship is in a box. Her words, not mine."

Jackson believes if she had found out about her partner's violent past before she moved in with him she may have been able to leave.

"He was violent, manipulative and controlling towards three women, he had a history and he served a sentence three years ago for GBH against a previous partner.

"For a case like that where the would be a track record - he'll be in the criminal justice system, he's in the safeguarding system because there are a children involved.

"He will be on lots of people's radars but not the women he's getting involved with. I can understand people are concerned about personal data being shared."

George Appleton

For Jackson it comes down to a simple point. The change in the law is because women have been killed, and currently are being killed at a rate of two per week by their partners or ex-partners: "If something like that keeps one of two women safer it's worth it. The reason this has come about is because women have been murdered. That's not a viable alternative."

But would women leave if they knew, and would they ask?

Karen Ingala Smith, chief executive of Nia, a service which aims to protect and help shelter women and children who have been victims of violence said she had "mixed feelings": "If professionals have an awareness that somebody's violent why would we want to withhold that from women who are entering a relationship with somebody who is violent.

"On the other hand we know that perpetrators work by isolating their victims, only 23% of victims go to the police. Often by the time women are aware somebody is violent the ties are already there," she told The Huffington Post UK.

Refuge have queried the resources Clare's law will use, but for Ingala Smith there is "never enough" cash to support victims of violence.

"We don't know that until we've tried it. Refuge are taking quite a simplistic position. I absolutely agree that police should respond to people's calls and take them seriously but if a woman is in a position where she is concerned, if she could get information that might help her make a decision, I don't think it's either-or."

Home office minister Lynne Featherstone said the point of the pilot was to see if it worked: “The figures are something like 25,000 known abusers with a history, and that can be gotten and used to an advantage, but that is what the pilot is for – to prove and understand whether the scheme works. After all, if people are working, we say you have to have a Criminal Records Bureau check, a CRB check for work, so it’s not a million miles to think that if there is a history that is inappropriate, that that might need to be available.”

Labour are also supporting the pilot, with shadow home secretary Yvette Cooper saying: "Victims of domestic violence or people who have concerns about the behaviour of their partner should have access to any information that could potentially save their life."

Michael Brown, the father of Clare Wood

Another person in favour is Clare Wood's father, Michael Brown, who has campaigned for the law change since his daughter's brutal murder. On Monday morning Brown said that if his daughter had known about her partner's violent past she would have "dropped him like a hot brick and scampered out of there." He told BBC Radio 4's Today programme that women deserved an opportunity to make an "educated decision."