The secret Facebook groups where women shame their exes

Claire wanted to warn other women about her ex-partner, who abused her

Thousands of UK women are naming and shaming their exes on closed Facebook groups - their claims ranging from infidelity to violence, rape and child abuse. They say they want to protect others, but experts say they risk their own safety.

Claire describes herself as just one of "an army of women, looking out for each other all across the country".

She is a survivor of domestic abuse, telling the BBC's Victoria Derbyshire programme how she was "pushed, dragged around, and thrown on the floor" by her ex-partner.

It has left her with depression, and days where she feels unable to open the curtains, or leave the house.

Her ex was charged with battery. He had to serve community service, but then returned to her home town.

Claire moved away to protect her children, but she wanted to warn other women of his history. So she decided to post on one of a series of UK-based Facebook pages known as Prick Advisor.

The group, with 100,000 members on its main national page and regional pages with numbers ranging from the hundreds to 40,000, promotes itself as a place where women can warn others of an ex-partner, or someone on a dating site.

Allegations range from cheating and catfishing (pretending to be someone else online) to serious abuse cases - with the alleged perpetrator's name, location and photo given.

Claire hopes that by posting she will have helped keep another woman, or family, safe.

"Just knowing that one person can be free from him," she says, "that feels like an accomplishment."

Samantha Wright believes the pages enable female survivors to have a voice

An estimated 1.3 million UK women experienced some form of domestic abuse in the year ending March 2018, according to the Office for National Statistics. But only 18% of those who were targeted by their partner reported it to the police.

For Samantha Wright, a regional administrator of a Prick Advisor group, the pages are a way of helping women "failed" by stretched local authorities and police.

One page contains a database of men who can be searched by name, to see if there has been an alert about the individual.

There is already a similar, official initiative - Clare's Law - which gives women potential access to a partner's criminal history.

But Samantha says it is not publicised well enough by police, meaning many women do not know it exists.

'Hunted down'

On Prick Advisor, women can post about men who have never been convicted.

Samantha says they ask women "to provide as much information as possible", such as screenshots of incriminating conversations.

But the charity Women's Aid fears this presents "serious risks".

Its public affairs manager, Lucy Hadley, says women could be "hunted down" by the alleged perpetrator, if word got out.

She also worries women joining the groups are "not getting the right expert information and support they need" from qualified professionals, and that images of domestic abuse on the pages risk causing psychological harm and triggering damaging memories.

There is also the possibility that women posting allegations could end up in court being prosecuted for libel, she says.

'Daddy hurt me'

It is a risk Marie - not her real name - was willing to take.

Her ex-partner's full name, location and picture were posted on the site by a friend - alongside the allegation that he had raped Marie's young daughter.

The three-year-old had begun having night terrors and become incontinent, when she told her mother that "Daddy hurt me" - leading Marie to suspect the abuse.

Marie went to the police. She says officers told her there was physical evidence of penetration, but did not feel it was strong enough to take it to trial.

Feeling she had been let down, Marie's friend posted about the man in the group to warn others about him being near their children.

Women's Aid says women writing the posts could be putting themselves in danger

By allowing any member to post allegations on the pages, though, there is also the risk that Prick Advisor will be used by some to post false claims.

One man, "Billy", describes the groups as like a "public hanging of men", after his ex accused him of controlling, abusive behaviour.

He strongly denies the claims but says, when word got out in the local area, it left him scared to leave his apartment.

"How can I prove my innocence when this woman that I only met for a short while is calling me everything?" he asks. "It actually had an effect on my business - people stopped coming to me [with work]."

'Feels like an accomplishment'

Asked about the legal implications in her case, Marie says she is "not bothered" about her ex's identity being shown - or the danger in which it could place him.

"He's ruined mine and my daughter's life. People need to know what he is," she says.

The page on which Marie posted was later suspended by Facebook, and the post is no longer up on the site.

A similar suspension happened to Samantha's regional page after it broke "community standards" - but control of the page was later handed back.

Facebook told the BBC in a statement that it has "strict rules on what is and isn't allowed, and [we] don't tolerate harassment and bullying that targets people or 'names and shames' them".

It added: "However, for criminal allegations such as sexual harassment or assault we recognise that it's important that people have the ability to raise awareness, therefore in these instances, depending on the context, we will leave these comments up."

Samantha says if her page was permanently removed, she would create another one - because of the importance of "giving these women the chance to speak out".

"You don't want to see [a man] just go on to do the same thing that they've done to the last person," she explains.

Follow the BBC's Victoria Derbyshire programme on Facebook and Twitter - and see more of our stories here.