The Welsh Government is to begin an official investigation after PinkNews.co.uk exposed that the Catholic Education Service has asked more than 300 English and Welsh schools to promote the Coalition for Marriage’s anti-gay petition, that asks the British Government not to go ahead with prime minister David Cameron’s pledge to introduce marriage equality in England and Wales. Experts anticipate that an investigation will also be announced by the English Department for Education.

Yesterday PinkNews.co.uk reported that in London school, St Philomena’s Catholic High School for Girls in Carshalton, students as young as 11 were “encouraged” to sign the anti-equality pledge by the school’s headmistress. The Catholic Education Service, which is responsible for hundreds of state funded Catholic schools confirmed to PinkNews.co.uk that it had written to at least 359 Catholic state secondary schools in England and Wales asking them to draw attention to a letter by senior archbishops which told Catholics of their “duty” to do “all we can to ensure that the true meaning of marriage is not lost for future generations”.

It also asked schools to “draw attention” to the Coalition for Marriage campaign and petition against civil marriage equality, which now has over 460,000 signatures.

It confirmed the presentations for all age groups had consisted of the Archbishops’ letter and ended with a slide displaying the Coalition for Marriage’s website and the words: “Sign the petition”.

A sixth form student told PinkNews.co.uk of her experience: “In our assembly for the whole Sixth Form you could feel people bristling as she explained parts of the letter and encouraged us to sign the petition.

“She said things about gay marriage and civil partnerships being unnatural. It was just a really out-dated, misjudged and heavily biased presentation.”

This evening, a spokeperson for the Welsh Government, which is responsible for matters such as education in the principality said that the Welsh Education minister Leighton Andrews has asked his officials to investigate. They told the BBC: “The education minister has seen the press stories and has asked officials to investigate.

“All schools must ensure issues are taught in a way that does not subject pupils to discrimination.”

Conor Marron of the Coalition for Equal Marriage told PinkNews.co.uk: “We welcome the Welsh Government’s announcement of an inquiry and it is admirable that they have acted so quickly after PinkNews.co.uk’s expose. The administrations of these schools need to be held to account for upholding prejudice and bringing politics into the school halls. However, we can’t keep this limited to Wales. We call on the English Department for Education to initiate a full inquiry to ensure the law is enforced and that children are free to make up their own minds.”

The school and the Catholic Education Service is already facing the threat of legal action from the British Humanist Association following the PinkNews.co.uk exclusive investigation. The British Humanist Association said it believes such actions may have violated section 149 of the Equality Act which prohibits discrimination on grounds of sexual orientation and sections 406-7 of the Education Act 1996, which forbid the “promotion of partisan political views in the teaching of any subject in the school”, and requires balanced treatment of political issues.

BHA Faith Schools Campaigner Richy Thompson said: “This action by the Catholic Education Service is absolutely outrageous. Not only might this break equalities legislation, it also breaks laws against political partisanship. If any pupil at one of the schools concerned is interested in challenging this practice at law, we urge them to get in touch with us.”

Chair of the Accord Coalition, Rabbi Dr Jonathan Romain MBE said: “Schools should teach about a range of religious and cultural perspectives surrounding matters of sexual diversity and gender. However, first and foremost, they should have a duty to promote an acceptance of sexual diversity and transgendered people that should trump all other considerations, which should be embraced with enthusiasm.

“When many LGBT staff and pupils have a concealed miserable experience at school, and we know that homophobia is worse within the faith school sector, it seems therefore all the more inappropriate that the Catholic Education Service of England and Wales should ask Catholic schools to advance a one sided perspective on same sex marriage, and for their pupils to advance this as a political aim.

“The Education Service have shown a shocking disregard for the condition of LGBT people; have failed to properly embrace the much more important obligation of ensuring that everyone is treated with respect and kindness, and in doing so have undermined public trust.”

The eQuality project, part of London’s LGBT mental health charity PACE, said putting pressure on young people to respond in a particular way to the equal marriage question could make it hard for those who have different views to voice them safely.

Tim Eastwood, eQuality Co-ordinator said: “Positioning young people in such a way as to encourage discrimination is clearly going to result in further inequality, in a society which prides itself on being equal and just.”

eQuality questioned whether the school in question yesterday at which pupils were said to have been “encouraged” to sign the petition, could have instead directed them to the Home Office public consultation on marriage equality, where they could respond “in a way which encourages thoughtfulness and analysis”.

The Catholic Education Service issued a statement today saying the Archbishops’ letter, as well as the Coalition for Marriage campaign, is a “positive affirmation of marriage”.

It said: “We reject the suggestion that Catholic schools have acted illegally. The Equality Act 2010 applies to all schools and we are fully supportive of the Act. It is central to Catholic teaching that all individuals should be treated with respect and dignity.

“Catholic state schools have always been permitted by law to teach matters relating to sex and relationships education, including the importance of marriage, in accordance with the teaching of the Catholic Church. The Catholic Church’s view on the importance of marriage is a religious view, not a political one.”

The Catholic Education Service’s deputy director was not aware of the age restriction on the Coalition for Marriage petition when contacted by PinkNews.co.uk yesterday about the presentation a Catholic state school in south London had given to girls as young as 11 which ended with the words “Sign the petition”.