Jamie Barry turned up at Welford primary school on 3 October expecting a routine meeting of the twice termly parents’ forum – about 20 mums and dads, there to discuss issues such as the annual community festivals and home-school diaries. Instead, the headteacher found five times that number of parents and one item on the agenda: the Birmingham school’s recent introduction of a range of teaching materials called Chips – Challenging Homophobia in Primary Schools.

Some parents had been supported by Safe at School, a campaign run by the anti-abortion group the Society for the Protection of Unborn Children (Spuc), which had emailed them a list of questions and comments to make (see below). “Teaching children about sexual orientation isn’t making them safe,” point 12 says. “It’s putting ideas into children’s heads.”

Part of the email sent by the Safe at School campaign, linked to an anti-abortion group, suggesting questions for parents at a meeting with Barry, to which the police were called.

As the meeting became more heated, a group of around 10 parents came to the fore. Their complaints became, in Barry’s words, “very personal and very aggressive”. Homophobic abuse was directed at the head, alleges Cllr Brigid Jones, Birmingham city council’s cabinet member for children and family services. Eventually, increasingly concerned staff called the police, and Barry was advised to leave the room and wait in his office.

A month later he chooses his words carefully when talking about the incident and keeps his description brief. He wants the school to move on, he says, and refutes reporting that claimed he had been “escorted from the premises for his own safety”. Others are more outspoken: Jones calls it a “dark and horrible episode”. Rob Kelsall, the National Association of Headteachers’ senior regional officer, says he was horrified by what happened.

Kelsall is calling on the DfE to give its “full support” to heads who deliver the Chips programme and find themselves in Barry’s position. “It’s about coming behind the head and the school to say ‘this is a fundamental value that there’s no negotiation on’,” he says. “We’re calling for more clarity on what is described all too often as ‘fundamental British values’. It’s about sending a message to the community that we teach respect of law and tolerance, and Chips is an important part of that.”

Chips was introduced to Welford, where 44% of pupils are from families of Pakistani origin and 22% from African-Caribbean backgrounds, in the wake of the Trojan Horse affair. The school, which has 480 pupils, in Handsworth, was one of 21 in Birmingham to be inspected in the inquiry into claims that Muslim hardliners had infiltrated some schools, and while it was given a clean bill of health, inspectors reported some children saying they believed it was wrong to be gay.

“We were aware that they might do, because culturally, within the community we serve, we know those views are heard,” says Barry, adding that there was no problem with homophobic bullying in the school. “But it made us think that as a school we need to do a little more in terms of teaching children about diversity and relationships.

“While we respect everyone’s right to a personal view, same-sex marriage is legal and some same-sex couples adopt or foster. Our children will come into contact with these people and we don’t want it to be a shock to the system.” Those at the meeting in October came from a variety of religious backgrounds, and included parents with no religious affiliation, he says.

The Welford protest comes at a time of confusion over new rules issued after the Trojan Horse affair, stating that all schools should promote the “British values” of respect for the law, democracy, equality and tolerance of different faiths and religious and other beliefs.

Last week, education secretary Nicky Morgan warned that faith schools must follow the rules, but the DfE dismissed any suggestion that schools would be forced to teach gay rights against their will.

The rules allow inspectors to censure schools that do not conform to the Equality Act, which encourages respect for lesbian, gay and transgender people, and other religions and races.

Ofsted tells inspectors to look at what primary schools are doing to tackle and prevent homophobic and transphobic bullying, Barry explains, including whether they’ve given lessons about different types of families. “It’s very clear from the guidance what we should be doing and we shared that with our parents,” he says. He’s full of praise for the inspectorate’s reaction – Michael Wilshaw came to visit and offered his full support, says Barry – and that of the local authority.

In fact, Chips is being used in 35 other Birmingham schools. Two years ago the council hired the award-winning teacher and campaigner Elly Barnes as its LGBT adviser for schools, and began rolling out her Educate and Celebrate teaching in secondary schools and Chips in the primaries.

Chips, written by teacher Andrew Moffat, uses existing story books as the basis to teach children that LGBT people exist, via acceptance and celebration of difference, and is designed to be woven into literacy or PSHE lessons, rather than standing out on its own (“It’s not a big lesson about being gay,” says Barry). It’s not about sex, and as it’s not part of sex and relationships education (SRE), parents have no right to withdraw their children.

Like Welford, Anderton Park, in Sparkhill, Birmingham, started using the resources this term. Year 1 pupils listen carefully as their teacher Rachel Dutton reads them “And Tango Makes Three”, based on the true story of Roy and Silo, two male penguins in New York’s Central Park zoo who hatched a spare egg given to them by a keeper and cared for baby Tango.

Afterwards, Dutton asks questions: “Why did the zookeeper think Roy and Silo were in love? Did he think they’re both boys, they can’t be in love?”

“No,” the children chorus.

“It’s usually a girl penguin and a boy penguin, but this time it was two boys – is that ok?”

“Yes!” comes the reply.

Later the children, who’ve already learned not just about same-sex families but also single-parent and adoptive ones, settle down to draw a family of their choosing. Amarah draws two mummies and a baby, while her friend Maysa goes for two daddies. Why have they picked those? “Because we like them,” says Maysa. “And they’re easy.”

Unlike Barry, Anderton Park headteacher Sarah Hewitt-Clarkson didn’t tell parents about Chips in advance, and has had no complaints at the school, where the vast majority of pupils come from Muslim families. “It’s just some books,” Hewitt-Clarkson says. “Lovely story books. I wouldn’t talk to parents if I was going to buy books about children in wheelchairs or children who are blind. We’ve just spent £9,000 on some new books for the library – I didn’t tell the parents about that.”

She is appalled by what happened at Welford. “It’s a shocking indictment of a part of society that adults could behave like that. I think if parents start kicking off like they did at Welford, they should lose their right to a free education [for their children]. British values are about the rule of law. The Equality Act is the law, so you can’t pick and choose that bit; it should not be negotiable.”

Safe at School, which campaigns for the removal of “sexually explicit” teaching materials from schools, says Welford parents are “worried sick about what is happening to their children” and fear Chips is “sexualising” them. A review of the scheme on its website states that although its author says he is only teaching children that gay people exist and that that’s OK, “Chips can also be seen as a programme for priming susceptible, small children for gay sex later on”.

None of the parents want to talk to the media, says Safe at School co-ordinator Antonia Tully, who got involved at Welford school after being contacted by parents earlier this year. “They told me that someone phoned the police which was a very inflammatory reaction,” she says. “They said nothing that happened at the meeting warranted any police involvement.”

Is she aware of homophobic comments being made? “I wasn’t at the meeting, I really don’t want to talk about it,” she says. Later in October she went with parents to deliver letters of complaint from 160 of them to the council.

One parent posting on Twitter, who described herself as white British and a Muslim, said the incident had been blown out of proportion. “It was not nasty at all, it just got very loud,” she said, adding it was “not a Muslim issue”.

“Homophobia is just as important as racism, sexism etc – but they are too young for this yet, it’s confusing,” one of her tweets reads.

A DfE spokesperson said: “We are committed to tackling all forms of bullying, including homophobic bullying, in an age-appropriate manner.” Frequent homophobic bullying in secondary schools had almost halved since 2009, she said. However, “Primary schools are not required to teach about relationships. If they do, it must be age-appropriate and done in consultation with parents’ wishes.”

Birmingham has never seen anything like what happened at Welford, says Jones. “This is 2014 and the behaviour of these parents has been extraordinary,” she says. “It’s appalling what they’re doing. Some of their children will grow up to discover they’re gay. How on earth are they going to feel about that? We’ve been clear in letting them know this is absolutely not acceptable.” Like Barry, she’s adamant Chips is staying put at Welford.

The quote of the week on the school’s website last week was from Maya Angelou: “Hate. It has caused a lot of problems in this world but not solved one yet.” There have been words of support from some parents, but it has been a difficult time for Barry nonetheless. “Not just because they made personal comments towards me, but because I came into teaching to make a positive impact on the lives of our children,” he says. “I know it sounds a terrible cliché, but I wanted to mould and shape the future generation. I don’t do anything just because I’m told to do it – I do things if I think they’re right.”