A solicitor from the Christian Institute has told a committee of MPs that a primary school teacher in London was previously disciplined by a head teacher for refusing to read ‘And Tango Makes Three’ – a children’s book about two male penguins looking after a female chick.

The Public Bill Committee of the House of Commons – made up of MPs who both have spoken against and in favour of LGBT equality – has been scrutinising the Marriage (Same Sex Couples) Bill for England and Wales since last month’s Commons vote.

In a submission to the committee, Samuel Webster, an in-house solicitor at the Christian Institute, revealed that he dealt with two cases – one involving a London primary school teacher in 2009 – the other involving a Scottish secondary school teacher in 2012 who claimed that teaching about same-sex marriage contributed to a breakdown.

In the first case, the teacher, referred to as “Mrs A” was covering a year 5/6 class in January 2009 when she picked out a book called ‘And Tango Makes Three’ from the book collection in the classroom.

Mr Webster said: “On the cover, it had a picture of penguins at the zoo. Mrs A thought it was a book about the zoo and decided to read it to the children. However, after reading the first couple of pages, she realised that it was a story book depicting a same-sex relationship between two penguins. She was shocked because the book was clearly written to promote to children the idea that homosexual relationships are equivalent to traditional marriage.”

Mr Webster continued: “Some of the children immediately realised what the book was about due to the part that their teacher had innocently read to them, although none of them seemed to mind her not finishing the book. Mrs A asked the children if they wanted her to explain why and they said they would. She replied that some people think that such relationships are okay. That’s their decision. However, others do not. The children appeared to have no problem with this. She then picked up another book, first scanning through it carefully, and the children didn’t mention anything else after that.”

The committee heard that Mrs A felt annoyed that the school had not informed her that it had acquired ‘And Tango Makes Three’, written by Peter Parnell and Justin Richardson. Published in 2005 the book is based on the true story of Roy and Silo, two male Chinstrap Penguins in New York’s Central Park Zoo.

It follows the six years of their life when they formed as a couple and were given an egg to raise. This egg was obtained from a male-female penguin couple, named Betty and Porkey, who had two eggs and could not care for both at once. Roy and Silo took turns sitting on the egg, and eventually it hatched. The female chick was named Tango by the zookeepers.

LGBT campaigners have praised the book as a valuable educational resource – but anti-gay opponents in the US have in the past attempted to ban the book from public libraries.

Mr Webster said Mrs A “felt that she had dealt with the incident in class in a measured and responsible manner while maintaining the integrity of her faith. She also believed that her response was consistent with the teachers’ code of conduct.”

However, a few days later, the school’s head teacher asked Mrs A why she had not read the book to the class after speaking to several students. Mr Webster said that Mrs A felt “as a Christian she could not read such books because she would then be promoting homosexual relationships as morally acceptable.”

But the head teacher responded by saying that decision went against the law.

Soon after the incident, Mrs A was restricted from having her own class in the new school year.

In the meeting when this was explained to Mrs A, her head teacher told her: “The school policy will soon be to promote homosexuality which will include the reading of books in class”.

Mrs A subsequently became a support teacher in the school.

Last month, Education Secretary Michael Gove told the committee that the same-sex marriage bill for England and Wales poses no threat to teachers who disagree with the reform.

Earlier this week, the Christian Institute became the latest group to criticise PinkNews founder Benjamin Cohen and the BBC for broadcasting a talk which likened the treatment of gay people in Britain to the crucifixion of Christ.