The young men and women blowing clouds of grape and mint-flavoured smoke at a Middle Eastern shisha cafe in Sydney could pass for any group of friends.

They are a cluster of ordinary professionals and students, passing hookah pipes to each other, as they sip coffee, banter and glance at their smartphones.

The circumstances under which they know each other are bittersweet. They are members of an underground network of former Muslims across Australia, caught between secularism and Islam. Some fear persecution if their loss of faith is discovered, some fear for their lives.

Melbourne local Aisha* is one of more than 70 members of the network spread across the country.

Aisha was cut off from her family three years ago when things took a dark turn after she removed her hijab.

"I never actually told my parents I was an ex-Muslim because I was scared of their reaction," she said.

"The most that happened was when I took my hijab off, one of my friends put a photo on Facebook and my parents ended up seeing it.

"They were pretty upset and said I was obviously just a whore who would end up dead in the gutters."

She said her parents, whom she described as "moderate, even liberal", turned physically violent and police got involved.

Aisha, in her 20s, was forced to move out of the family home.

"My parents were claiming I was a compulsive liar."

Her identity has been protected because she is still afraid of possible consequences, like most people in this network.

"When you think about it, over a billion people still follow Islam. If it brings them comfort let it bring them comfort. I think the issue is when it starts to infringe on our right to live," Aisha said.

The members we met recounted stories of either being disowned by family, forced into silence, shamed or demonised by community leaders and clerics, and having to pretend they were Muslim to avoid issues.

The abuse can be psychological, verbal, physical, and also financial for those who are dependent.

Staying low-key
For many Australians, it is not unusual to be casually open about their atheism or agnosticism. Thirty per cent of Australians described themselves as having "no religion" in the 2016 census.

But it is different for many who have been raised Muslim.

In the last census by the Australian Bureau of Statistics, ex-Muslims in the secret group still embedded in their communities chose Islam as their religion because answering the census was a household activity.

Group members who spoke exclusively to the ABC said they led double lives and were afraid of "coming out". Many maintain a Muslim exterior at home, at work, in their communities, and at mosques.

Nadia*, another network member based in Melbourne wore a niqab — the face veil — when she was practising.

She runs an anonymous blog called Nullifidian, where she writes about her experiences being home schooled and raised in a strict Muslim household.

Nadia, in her 20s and also ostracised from family, covers her hair and most of her face in online videos in order to remain disguised and anonymous.

She told the ABC Australian ex-Muslims had a simple wish.

"Ex-Muslims just want to live their life how they need to without fearing disownment, isolation, imprisonment or death," she said.

In one blog post, she explained: "I choose to remain anonymous online because although I live in a western country, I have endured so much abuse and threats from the Muslim community where I live.

"I also choose to remain anonymous because I have previously been doxxed by Muslims who went as far as to try and get me fired by contacting my workplace."

Losing their religion
There is a week left until the end of Ramadan, the Islamic month of fasting. Since mid-May, Muslims have been abstaining from food and water from sunrise to sunset.

Aisha said she was feeling nostalgic.

"I miss Ramadan heaps," she said.

"Ramadan always came easy for me. I loved fasting, the food, the sense of doing something for a higher purpose. For me, [it] was a time of joy because my family all came together."

Only a few years ago, Aisha would have been fasting and praying. She would have left the house wearing her hijab, a long dress over a pair of jeans, and sneakers. She had been an extremely devout Muslim most of her life.

"I left Islam because I disagreed with things in the Koran [Islamic holy book] and I couldn't comprehend the idea of disagreeing with things in the Koran and still believing in Islam.

"We're told the Koran is the word of God, not a word has been changed since its existence, which means every single thing in the Koran has to be true.

"If you don't believe in one sentence of the Koran, how can you believe in the religion?"

'We were just kids on the internet, we were not activists'
The Australian network is part of a global ex-Muslim network that started online roughly seven years ago on Reddit, a social news aggregator.

Imtiaz Shams is a vocal British ex-Muslim, who moderates the online Reddit community /r/exmuslims, which is one of thousands of subgroups.

He said he has watched the page grow from several hundred subscribers to more than 30,000 currently.

Imtiaz was a crucial part of establishing the network in Australia.

"If you talk about ex-Muslims, you have to talk about the internet," he said.

"When I left Islam, I thought I was the only one in the world.

"For … years, I spent my time building ex-Muslim communities that are like Fight Club style, you know, you have to know someone to get in across the world with my friends.

"We were just kids on the internet, we were not activists.

"When you go on Reddit, every day you come across those stories [and you think], 'Oh my god, I thought I was the only one'."

Group members stay in touch on Whatsapp and Facebook, and meet up in real life. The process of joining the network is rigorous and there are strict verification methods the ABC cannot divulge.

In 2015, Imtiaz established the UK-based group Faith to Faithless, which is a not-for-profit group assisting all ex-religious people, including Mormons and Orthodox Jews.

"There are many, many cases where there have been failings with these social services when it came to people like us," he said.

"And these failings can lead to mental health trauma, being put back into an abusive situations, groups, communities, even cults."

Ex-Muslims told they are taking things 'out of context'
Former Muslims told the ABC they had been accused of being mentally ill, being hurt and lost, of not understanding Islam properly, taking scripture out of context, or just wanting to have sex and drink alcohol.

Some have also been accused of never having practiced true Islam and conflating bad experiences with Muslims with the religion itself.

The Arabic term for apostates is murtad, which is used as a slur. Ex-Muslims are also referred to as munafiqun, which translates to hypocrites, and are accused of trying to undermine the Muslim cause and causing unrest.

"One myth I have come across quite often is that ex-Muslims are weak-minded individuals [who] have been corrupted by western ideas and propaganda," Nadia said.

"This sort of thinking is wrong because it says that ex-Muslims cannot think for themselves, that they are lacking in the ability to reason and think logically."

Ali Kadri, the vice-president of the Islamic Council of Queensland, said "most ex-Muslims I have heard from leave Islam because of some issues they have had with Muslim community or their families".

"Unfortunately, a lot of social ills are justified by Muslims in the name of Islam. That is because of ignorance of Islamic teachings and those ex-Muslims who are victims of it blame Islam and all Muslim community for what they may have faced.

"This in itself is because of ignorance of the faith and proper teaching of Islam."

In reality, ex-Muslims explained that the moments in which they could feel themselves moving away from Islam were agonised over and were not taken lightly.

That made dealing with comments that they, "never knew anything about Islam" or were not taught properly more offensive.

Many said it was knowing Islam so well that allowed them to look at it critically.

And they argued that regardless of their reasoning, they should be legally and socially able to opt out of a religion and to be safe from judgement and abuse.

Imtiaz said there were many accusations that ex-Muslims were merely chasing worldly pleasures.

"If you wanted to do that [have sex, drink alcohol], why wouldn't you remain Muslim?" he said.

"A lot of Muslims can just get away with that. In fact it's quite easy if you live that [particular] double life.

"It's harder to be an ex-Muslim because that's a choice you've made, that's like a theological position you've taken."

Where does Islam stand on apostates?
In a Koranic verse, it says there is "no compulsion in religion". In another, it states apostasy is punishable by death and there are several mentions of hellfire as punishment for disbelievers in the afterlife.

There are several hadith — sayings of the Prophet Mohammad — that are broadly agreed to be "authentic" and "correct" by Sunni Muslim scholars that also state leaving Islam is a sin punishable by death.

In 23 Muslim-majority countries, apostasy is a crime. In 13 of those countries, apostates get the death penalty, however in some of those countries, it is not enforced by the state.

While there is some protection given to freedom of religion in the Australian constitution, ex-Muslims still choose to be careful because the price to pay for leaving the faith can be high.

And the community they now fear, they used to call their own.

Sydney scholar Sheikh Ahmed Abdo said: "You could easily pick and choose verses from the Koran and shape whatever narrative you want … if they're not taken in a holistic manner."

He said apostasy carried a capital punishment in classical Islamic legal manuals, though added: "The punishment for apostasy is usually included in sections dealing with rebellion and political warfare."

"People are free to choose to embrace Islam or leave Islam, just like they're free to make choices in how they live their lives."

He added: "No-one should be calling to kill an apostate in lands where Islamic law is not applied."

Echoing this was Ali Kadri, the vice-president of the Islamic Council of Queensland, who said he put the questions the ABC asked to Islamic scholars.

"As Muslims, we abide by Australian laws and in Australia apostasy is not a crime," he said.

"[The] Koran is highly contextual. Only the extremists — Muslims and non-Muslims — use such verses out of context to further their agendas."

He said the verse was, "contextual to a time of war and turbulence".

"No mainstream Muslim scholar in Australia has ever advocated for such punishments," he said.

"Every faith considers leaving of that faith to be a sin and it is not illegal to believe so."

Even if there was scholarly contention about ex-Muslims being punished for leaving the faith under specific circumstances, they said language about apostates, disbelievers and women informs those perspectives.

Melbourne local, Fatima*, who is Muslim to her community but a non-believer in private, said: "People call us selfish, Muslim-hating, ignorant.

"This leads us to be demonised. All we want is to just live our lives, without this religion."

Aisha recalled reading verses she disagreed with.

"I remember reading the Koran a few times over and it never quite sat right with me, how men are allowed to beat their wives," she said.

"No matter how you interpret it, whether it's [to hit your wife with] something no bigger than a tooth pick or something meant to embarrass your wife and not hit her.

"She's an adult. She shouldn't be hit … she shouldn't be made to feel embarrassed.

"The fact a woman's word is worth half a man's [in a court of law] … I mean that's in the Koran itself.

"It just unravelled, really, really, quickly. It's like I picked a thread and as soon as that thread was picked, it kept unravelling."

The Australian National Imams Council and Grand Mufti's office did not respond to interview requests. The Board of Imams Victoria declined to comment.

The United Muslim Association and the Centre for Islamic Thought and Education did not respond to questions.

'I still remember the first time going out with bare legs'
On the topic of sex and alcohol, Aisha said: "I didn't move out of home or leave Islam to do those things.

"When I was religious, I never felt like I missed out when I was Muslim or jealous of not being allowed to drink.

"I still remember the first time going out with bare legs," Aisha said, recalling when she wore a skirt with tights in public.

"My friends had to drag me along because my tights ripped and they kept saying, 'No-one is going to look at your legs, it's fine'.

"I don't dress anything close to what I used to."

Nadia said the accusations flung at ex-Muslims were a kneejerk response.

Some of the indictments levelled against her include being "obsessed" with Islam. Muslim critics online have asked why ex-Muslims still associate with their Muslim past.

"Nobody wants to believe the things that they have been taught their whole lives may be wrong," Nadia said.

"Muslims have been taught from birth that their way of life is the rightly guided one and anyone who is not on the straight path is wrong and evil.

"So when someone comes along and questions the beliefs and thinking that many Muslims have known their whole life, it shakes them to the core and they believe it is their God-commanded duty to fight back.

"Most Muslims will attempt to ridicule and mock ex-Muslims for leaving Islam, calling them liars and hypocrites. However, in some cases overseas, Muslims will imprison, torture and even kill ex-Muslims."

Punishment and death is either state-sanctioned or carried out by vigilantes. In 2015, American-Bangladeshi blogger Avijit Roy was hacked to death at a book fair in Bangladesh.

Roy was the creator of an online community called Mukto-Mona for South Asian atheists, humanists and freethinkers.

Ultimately, Australia's secularism has created a buffer of safety for ex-Muslims.

Sadia*, a Tanzanian born woman living in Australia, said it was easier to believe and live how one wanted, regardless of their faith or lack thereof, in Australia.

"[It's] easier being an ex-Muslim in Australia compared to other countries I've lived in, like Malaysia and Tanzania," she said.

"Australia is not as influenced by religion, unlike the other countries."

Regardless of her new life in Australia, she acknowledges she will always carry her Islamic heritage with her.

"Growing up, everything was centred around Islam [so] I do feel culturally Muslim."

'We don't want to…ostracise people'
The vice-president of the Islamic Council of Victoria, Adel Salman, said: "What we don't want to do is ostracise people.

"I don't want anyone to feel that they are afraid — as Muslims we have enough of that with Islamophobia and anti-Muslim bigotry.

"As a community, our response [to people who leave] should be, 'Why? Let's talk about it. What experience have you had that led you down this path?'

"It is actually a big deal when someone leaves Islam. It is highly unusual so there's going to be a reaction.

"Muslims hold Islam as the very centre of their being, an essential part of their identity, so when ex-Muslims say, 'Look, I'm no longer [Muslim]', and they start criticising Islam, it's offensive.

"It carries extra offence when it's from someone who used to be Muslim."

He said it, "comes as a surprise" because that "bond" can feel broken.

'Cultural' Muslims, atheists and free-thinkers
Despite attempts to categorise ex-Muslims as heretics who have no place in Muslim communities, Sydney member Shaima said she considered herself a cultural Muslim.

"A lot of us can't shake the fact that a part of us is Muslim," she said.

"Whether it's our name, whether it's our faces, whether it's our mother, whether it's our father, that's all part of us and that's all part of our identity.

"The move to accepting Muslims and, in particular, Middle Eastern Muslims in the Australian landscape can only serve as a benefit to ex-Muslims.

"The more we're accepted, the more humanisation of Muslims there is … the more people will realise, we're not all the same, not everybody's the same.

"Going to these meet-ups is really an experience that I can't really compare to anything. You do kind of feel like you have a community."

Mr Kadri said if somebody leaves Islam, "They are no longer part of a Muslim community".

"Islam is not a cultural group but a religious one. This should not mean they should be ridiculed, threatened or persecuted," he said.

"But if someone decides to leave Islam or, as matter of fact, any religion, they should not complain if they are not considered as part of that faith community."

He said people of other or no faiths were still welcome to celebrate festivals and participate in cultural events.

Back in Sydney, Mohammad* said he was "out" to his immediate family and close friends.

"I would rather not be out to the wider Muslim community because I am worried about the impact it can have on my family, in terms of reputation, safety, and also future financial prospects because I work with a lot of Muslims," he said.

"Many of the views ex-Muslims hold towards Islam, the Koran and Mohammed could be very offensive or insulting to a Muslim person. It can definitely be frustrating to talk and act in a way that is 'acceptable' to Muslims because it doesn't feel very authentic."

Mohammad is trying to fast in the month of Ramadan because he does not want to upset his family.

Ex-Muslims do not want to be 'weaponised'
Australian ex-Muslims also worry about speaking out because they do not want to fuel anti-Muslim and anti-immigration rhetoric.

Ex-Muslims are politically diverse, and many do feel Muslim communities in the West are demonised but that it should not stop people from criticising Islam.

Mohammad said it seemed like the Right were, "the only side of politics willing to critically discuss Islam and its issues".

"Unfortunately, it is not uncommon for such discussion to devolve into bigoted rants about Muslims and their intentions in Australia," he said.

"As an ex-Muslim, I welcome critical discussion about Islam, but I view generalised statements against Muslims as an attack on my Muslim family and friends.

"There are clearly some issues in Islam and in the Muslim community but I believe scapegoating does nothing but cause more division and unrest."

Aisha said: "Right-wing people use [ex-Muslims] to justify their hate of Islam, in a way, and just be racist.

"I left Islam because I didn't believe in certain aspects of it and Islam is a religion based on everything being true."

The number of ex-Muslims likely to keep growing
The Australian group has no formal presence like its US and British counterparts — Ex-Muslims of North America (EXMNA) or Council of Ex-Muslims in Britain (CEMB).

It continues to remain low-key, but is slowly growing.

In the United States, 23 per cent of Americans raised as Muslims no longer identify with the faith according to the Pew Research Centre.

Nadia, who is in touch with ex-Muslims all over the world, said she was, "shocked at how many people had gone through similar experiences as me despite us being countries apart".

"If you look at countries like Saudi Arabia and Pakistan, ex-Muslims are believed to be in the hundreds of thousands," she said.

"I believe that there are so many more ex-Muslims in Australia than just the few that are part of the Australian group."

The community might be small, but it is significant to its members and allows them to live part of their life authentically.

Those people sitting around smoking shisha are also providing places to stay and connecting new members to official support services.

What started as "just kids on the internet" has become a cultural lifeline for members waiting for a time when they can lose their faith without losing everything else.