Senior lawyers and women’s organisations have condemned the increasing use of “rough sex gone wrong” as a courtroom defence to the murder of women and called for a change to the law in the UK.

In the wake of the conviction of British backpacker Grace Millane’s killer in New Zealand, researchers have revealed a tenfold rise over the past two decades in the number of times similar claims have been made in UK courts.

According to the campaign group We Can’t Consent to This, in the past decade 30 women and girls have been killed in what was claimed to have been consensual violent sexual activity in the UK.

Of those, 17 resulted in men being convicted of murder, nine led to manslaughter convictions and two ended in acquittals. In one further case, there was a murder conviction but only after the victim’s husband confessed; police had initially treated the death as non-suspicious. The case of one woman’s death has yet to go to court.

In 1996 there were two cases in which deaths and injuries to women were blamed on “rough sex”; by 2016, that had climbed to 20 cases a year.

During the Auckland trial of Millane’s murderer, the accused’s lawyer, Ian Brookie, told the jury that the 21-year-old backpacker had died during “a perfectly ordinary, casual sexual encounter between a young couple … as a result of what they consensually engaged in.”

The jury, however, did not believe him and unanimously found the killer guilty of murder. “You can’t consent to your own murder,” the crown prosecutor Brian Dickey said.

Fiona Mackenzie, an actuary, set up We Can’t Consent to This after the outcry over the killing of Natalie Connolly, 26, by her partner John Broadhurst, 40. Despite having 40 separate injuries, including serious internal trauma, a fractured eye socket and bleach on her face, Broadhurst received a sentence of three years and eight months for manslaughter.

Mackenzie supports changes to the domestic abuse bill, put forward by the MPs Harriet Harman and Mark Garnier, to incorporate the principle of R v Brown into statute.

She told the Guardian: “As well as changing the law, we need to have an attitude change across the justice system. People need to stop buying into these ‘rough sex’ excuses.

“Everywhere you look in the world, there’s the same failure in countries’ criminal justice systems. It’s terrifying.”

Consent, which has increasingly entered popular consciousness as a key concept in rape cases, is no defence to injury, let alone death. The principle was established in a 1993 test case, R v Brown, in the House of Lords in which a group of men were convicted of assault and wounding even though their sadomasochistic victims had willingly participated in the violence.

The defence of “rough sex gone wrong” has no official status in law but can, campaigners claim, influence prosecutors to reduce a charge from murder to manslaughter or a judge to lower the eventual sentence.

Sarah Green, the director of the End Violence Against Women coalition, said: “Women monitoring femicides in the UK believe the so-called ‘rough sex defence’ is growing. It is deeply alarming and at worst reflects the fact that defence is, actually, a business where some are willing to ‘test’ approaches that might win in court. It sets women up to be harmed in life and grossly insulted after their deaths.



“We’re also appalled at the willingness of large parts of the media to uncritically reproduce this deeply misogynistic line. Editors need to get a hold of this now and stop the thoughtless and sensational communication of cases where women have died.”

Prof Susan Edwards, a barrister who teaches law at the University of Buckingham, believes strangulation should be made a stand-alone offence.

“Strangulation is the cause of death in around a third of all spousal homicides,” she said. “Now there’s a burgeoning use of [rough sex excuses] because there’s greater acceptance of BDSM [bondage and sadomasochism] in relationships.”

Thirty years ago, she said, the more common excuse from a violent partner would have been that they were provoked, that it was unintentional or they lost control.

Campaigners partly blame the cultural normalisation of rough sex on the growth of violent online pornography and books such as Fifty Shades of Grey with its themes of sadomasochism.

What is not so clear is whether there has been a significant rise in the number of sexual strangulation deaths or whether the excuse of “rough sex” is simply being deployed more often than in the past.

Karen Ingala-Smith, the chief executive of the domestic violence charity Nia, said: “Women don’t die from rough sex. Women die because men are violent to them.”

She said violent and degrading online pornography was “socialising young men into different expectations of what they are supposed to do in bed. Women are pressured, whether they’re conscious of it or not, to accept violence during sex and do things that weren’t commonplace 10 or 20 years ago.”