Linda Brusasco used to consider herself a reasonably decent person until she met Deborah Drapper, 13. "Have you ever told a lie, stolen anything, used God's name in vain, coveted anything?" Deborah asked the unsuspecting producer, who was making a documentary on Deborah. Ms Brusasco admitted that she had. "So you're a lying, thieving, coveting, blasphemer. Do you still think you're a good person?"
Ms Brusasco couldn't answer that. Yet more and more schools are dealing with exchanges like this as devout pupils attack their classmates for their religious beliefs, or lack thereof.
One of the most recent examples was when five-year-old Jasmine Cain told a fellow pupil that she would "go to hell" if she did not believe in God. The pupil became distraught and reported the incident and an argument of biblical proportions ensued.
A teacher at Landscore Primary in Crediton, Devon, reassured Jasmine that she could talk about Jesus, but asked her not to tell the other children that they were going to hell. Jasmine told her mother, a receptionist at the school, that she had been banned from talking about God, the national press got hold of the story and Gary Read, headteacher, was bombarded with more than 300 emails and letters, including threats to kidnap his children, brand him a child-molester and torch his house.
These are not isolated incidents, confirms Hanne Stinson, chief executive of the British Humanist Association. In fact, she thinks they may be increasing as evangelical communities become more outspoken.
"Generally speaking, if one religion becomes more vociferous in its demands, others will follow suit," she says. "Teachers may try to avoid these situations, but they are bound to occur, so they need to know what to do about them."
Ms Stinson's own daughter tearfully asked her if she was a "bad person" when she was eight years old. It turned out that a fellow pupil had told her that she must be because she did not pray or go to church.
"If children are told that that is the absolute truth at home, and have no opportunity to explore other opinions in school, they could go through their whole childhood without ever challenging those beliefs," Ms Stinson says.
That certainly seemed to be the case with Deborah Drapper, who was the star of Deborah 13: Servant of God - which aired on BBC3 in March. She was home educated and relatively sheltered from the world beyond her creationist parents and 10 siblings.
In schools, however, teachers try to promote a culture of mutual respect, tolerance and co-operation between pupils who follow different faiths or are not religious. A lot of the difficulties come from semantics, believes Tom Bennett, head of RE and philosophy at Raine's Foundation School in Bethnal Green, east London.
Saying someone is "extremely religious" implies extremism, he says, whereas religious people can be immensely tolerant and inclusive. The same applies to fundamentalist beliefs, he argues. "Many of our parents and students are passionate about Jesus or Allah, but are perfectly happy to sit in a room and discuss differences with Buddhists and Sikhs," he says. "Religion does not by itself generate intolerance and antisocial behaviour, people's personalities do that."
Tapping into various ideologies - even where overtly religious - can enrich classroom activities and discussions, says Dr Michael Hand, reader of education philosophy at the Institute of Education in London. "They can undoubtedly cause some problems in schools, but the whole justification for comprehensives is to bring pupils together from lots of different cultures and backgrounds. Through open discussions they can learn from each other."
Censoring or suppressing pupils' opinions could drive dogmas underground, he adds. Instead, schools should harness children's views in class debates, with teachers ensuring alternative (but never overtly offensive) opinions are heard.
"It's beneficial to the child if they can articulate their beliefs," Dr Hand adds. "By putting them in a questioning environment, they will be better equipped for our multi-cultural society, as opposed to getting locked in to a narrow, sometimes oppressive world view."
In contrast, mono-faith schools may reinforce already entrenched opinions, opponents argue. "The expression of strong religious views by pupils in religiously segregated schools is actively encouraged," argues Mike Lake, an ex-primary school teacher from Derby and founder of the Derbyshire Secularists and Humanists group.
But faith schools neither cause or prevent pupils from imposing their strong religious beliefs on others, believes Mr Bennett, who works in a CofE school. "Allowing schools to teach different things in different ways will contribute to a healthier, more cultivated society with broad, diverse opinions," he says.
Mr Bennett does sometimes encounter parents who want to promote their own religious or secular beliefs in the school's curriculum, plus those who take offence about what is being taught. "But frankly, I don't lose much sleep over it. If adults want to preach to their kids, then the law allows them to do so at home." At schools, however, teachers need to steer clear of proselytising.
That does not stop some adults from trying to exert influence. A campaign by two Muslim governors to make a primary school more Islamic was partly responsible for forcing a successful head from her job with stress, the High Court found this March. Erica Connor, the former headteacher of New Monument School in Woking, Surrey, was awarded pound;400,000 in damages after Surrey County Council failed in its duty to protect her against false accusations of Islamophobia.
With parents like this, it is little wonder that children sometimes espouse "controversial" religious leanings. But we should come to expect different views, rather than fear them, says Jane Brooke from the National Society for the Church of England, especially when looking at the numbers involved. Up to 80 per cent of young people believe in a God, according to a Beatbullying report, and half of these practise their religion. The proportion of practising adults is just 18 per cent.
"Most schools have a culture of respect where different opinions can be expressed," she says. "If a pupil gets upset from something said in the playground, a good primary school will bring the issue back into a circle time or assembly discussion. Anything controversial can be explored and dealt with in a safe environment."
In that way, an inflammatory religious remark is treated in a similar way to a racist slur. Teachers need to use their professional judgment to decide whether the comment is malicious or whether it needs to be discussed in private or as the basis for a whole-school discussion. "Teachers have to walk a bit of a tightrope," says Ms Brooke.
"On the one hand, they must accept who pupils are, but on the other they must encourage them to respect different people's viewpoints."
Every child will have an opinion that they think is right, adds Ms Brooke. Even an aggressive bully will usually try to justify their behaviour somehow. A teacher's role is to try to broaden the young person's understanding of a sometimes complex situation, and encourage them to view the world from other people's perspectives.
It is not always easy. Judith, a primary school teacher from Devon, used to teach an evangelical girl who was staunchly set in her ways. "It was exhausting trying to get her to tone it down," she says. "We all tried to introduce her to other ways of thinking, but eventually I gave up. I thought she'd grow out of it."
In the end, the eight-year-old's mother removed her from the school. "If you're that religious, chances are your parents will want you to mix with other children who share similar views and principles," Judith says. "Our school was too diverse for her."
For pupils who stay in mainstream schooling, they can explore various outlooks in religious education classes. Although RE is compulsory (unless parents use their right to withdraw their children from lessons), its content is not prescribed by the national curriculum.
Instead, each local authority in England and Wales is required by law to have a multi-faith Standing Advisory Council on Religious Education (Sacre), which suggests the RE content. The syllabus is meant to reflect the character of the local communities they serve - usually looking at all the major religions, plus allowing time to reflect on moral, social and spiritual elements.
"This is clearly not prosletysing or preaching," insists Mr Bennett. "The clue is in the name - religious studies. It is an analysis, not a sermon."
Teachers themselves may not be so neutral. Nearly a third of teachers would like to see creationism or intelligent design taught alongside Darwin's theories of evolution and natural selection, according to a survey of more than 1,200 teachers carried out by Teachers TV last November.
But schools that make a point of being neutral - by banning religious clothing or symbols for example - can also find themselves courting controversy. "Asking someone to leave their belief in God at the door . is akin to asking someone to remove their skin colour," the Archbishop of York was reported as saying earlier this year.
Margaret Nelson, a former art teacher and a member of Suffolk's Sacre, strongly disagrees. "Religion should be left at the school gates," she says. "If parents want faith to be part of their children's education, let them pay privately to send them to a faith school."
Banning pupils from similar discussions will not stop underlying tensions, which may sporadically erupt in severe violence or bullying. Instead, teach pupils about a diversity of opinions and provide a forum in which they can discover and explore their own views and beliefs, says Mr Bennett. "No controversy, no fuss," he maintains. For when has religion in schools ever proved controversial?
Bullied because of religion
A quarter of young people who practise a religion have been violently bullied due to their faith or for wearing religious symbols, according to a report from Beatbullying last November.
One of them is Dylan, a 13-year-old from east London who has been called a terrorist, a Paki and a stupid Muslim by boys at his school, despite actually being Hindu.
Teachers ignored the physical and mental attacks and Dylan started to miss school. "I felt like curling up into a ball and dying," he says. "I just wanted to be left alone."
Beatbullying now runs inter-faith bullying prevention programmes, funded by the Government, which have reduced incidences of faith-based bullying by 45 per cent in participating schools.
Emma-Jane Cross, chief executive of Beatbullying, says: "By providing outlets for young people to discuss the issues that matter to them, we can effectively reduce antisocial and violent behaviours between young people."