A type of man who declares himself involuntarily celibate. 

When is a terror attack not a terror attack? When the victims are women.

It would be hard not to draw this conclusion after recent horrific events in Sydney, Australia.

On April 13, Joel Cauchi killed six people and stabbed 12 more, including a nine-month-old baby girl inside the Westfield Bondi Junction shopping centre. The vast majority of the victims were women. This was no coincidence, as we would quickly learn.

The attacker's father Andrew Cauchi even admitted his son may have targeted women was because 'he wanted a girlfriend... He's got no social skills and he was frustrated out of his brain.'

That deliberately killing women is not considered ideological or extremist. Tell that to the one in three women on the planet who are raped or beaten in their lifetime. That statistic is not random chance.

Ideology is defined as a set of ideas or beliefs of a group or an individual. What is misogyny, then, if not an ideology? A belief system that has dominated patriarchal societies for thousands of years.

Mass murders of women by men who have made misogynistic statements or been involved in extreme misogynistic communities online are far from rare. But you probably haven't heard of most of them because motive is rarely mentioned. The perpetrators are not described as terrorists. The word extremism doesn't come up.

In 2014, Elliot Rodger murdered six people and injured 14 others in Santa Barbara, California. In a sickening manifesto, he wrote: 'I will destroy all women... I will attack the very girls who represent everything I hate in the female gender.'

As part of the killing spree, he targeted the Alpha Phi sorority (a female society at a university) whose members he deemed the 'hottest' at his college, 'the kind of girls I've always desired but never been able to have'.

Rodger had been heavily involved in so-called 'incel' websites and forums: where men who consider themselves 'involuntarily celibate' blame women for denying them sex, and plot their 'revenge' in the form of physical and sexual violence.

In 2021, Jake Davison carried out the first mass-shooting Britain had seen in a decade, killing five people and injuring two others in Plymouth, Devon.

Within 24 hours, police said they did not consider it a terrorist attack or linked to extremism.

This is despite Davison being active in incel forums, uploading misogynistic rants about women online. His mother had previously reported him to the Prevent anti-terror scheme.

Days before the shooting, he'd searched online for incel serial killers.

Alek Minassian told police he had been radicalised online and was acting in the name of 'incel ideology'.

'I was angry that [women] would give their love and affection to obnoxious brutes,' he said.

Minutes before he launched his deadly attack, he posted on Facebook: 'The Incel Rebellion has already begun! We will overthrow all the Chads and Stacys [names incels use to describe attractive men and women]! All hail the Supreme Gentleman Elliot Rodger!'

In such cases, killers are usually described as 'lone wolves', 'disturbed' and 'mentally ill'. There may well be components of mental illness in many such cases, but it is wrong and damaging to suggest that this is the sole issue. Mental illness is rarely mentioned when discussing acts of Islamist terrorism, for example, even when it is present.

Millions of people globally experience mental illness without committing acts of violence. And though mental illness might make someone particularly vulnerable to malicious ideologies such as misogynistic extremism, it doesn't mean we should ignore the role those ideologies play in events.

Jack Peterson is one of the thousands of young men who visit forums on  Reddit and other incel websites.  "I've had a couple of negative experiences in relationships and so that has made me feel, like you know... it's hard to move on from my past and start a new relationship," he says. "I've had women who have done pretty bad things to me."

These overall themes of failure and frustration - along with anger and hate - are common on incel forums.  They go to message boards out of loneliness. What they find is a group of angry men pushing the idea that they have lost the genetic lottery, and there's almost nothing they can do about it

The idea that all women are money-grabbing, promiscuous and manipulative comes across strongly on incel threads, where attractive women in particular are referred to as "Stacys".  "Stacys" are objects of both desire and ridicule.   In their world, incels believe "Stacys" will always choose so-called "Chads" over them.  A

"Chad" is a caricature of a sexually successful man. And comparisons are not just about personality or confidence. Many incels believe they are genetically inferior to "Chads".   These crude caricatures seem laughable - but they are important because they create an "us v them" mentality. Incels believe that sex, love and happiness are out of their reach, available only to others.

They're particularly drawn to the nihilistic "black pill" theory - the idea that they are the only ones who realise that the game of sex and attraction is rigged from birth.