Daily demonstrations have been taking place outside Anderton Park Primary School in Birmingham but Friday’s was the largest – and angriest – so far.
Flyers had been sent around the local community encouraging people to join protests against the school “brainwashing” children that “it’s okay to be gay”.
One man told Sky News he had joined the crowd because “homosexuality is a heinous, horrible thing”. Another said homosexuality is “not acceptable for us lot”.
But the protesters held banners that read “we are not homophobic people”. They chanted for the headteacher to quit.
The demonstrations are organised by Shakeel Afsar, who does not have children at the school.
He is being helped by Amir Ahmed, who ran protests at Parkfield Community School that led to the school suspending teaching of its equality programme, No Outsiders.
They had invited Abdullah Bahm from Batley, West Yorkshire, to join the crowd outside Anderton Park.
He said they had got in touch via WhatsApp and were planning a national campaign.
He showed Sky News the “parent packs” he was putting together, which included “horrific” images and information that he claimed was being taught to primary school children.
Mr Bahm told the crowd the protests so far in Birmingham were a “pilot project” for wider opposition.
“This is going to go national, parents are going to complain like this and schools had better get ready for it,” he said.
“They either throw the programme out or parents will withdraw their children odd days to make protests like they’re doing here.”
Parents involved in the protests at Anderton Park are stepping up their action by threatening to withdraw their children for a day on Monday.
There were tense scenes as protesters tried to challenge staff outside the school gates on Friday.
The headteacher, Sarah Hewitt-Clarkson, told Sky News “the vast majority of protesters are not parents”.
She said the outrage was “spoiling a child’s education, risking unauthorised absence fines, having unauthorised absence on a child’s records, creating division between school and families where there wasn’t any before”.
“All because it’s important for children to know and understand that some people have two mummies?” she added. “It is quite unbelievable.
“The few people spreading misinformation will have to wrestle with their own consciences.
“The lies and misinformation are becoming more extreme. It’s very sad that a few resort to this. Seeking to divide communities and plant doubt in children’s minds about the teachers they have known their entire school life is unforgivable.”