A Welsh Government investigation into PinkNews.co.uk’s revelation that the Catholic Education Service encouraged schools to promote a petition against same-sex marriage has concluded that this may have led to schools breaking laws on political balance.

The Government has also asked that any schools which promoted the petition now make pupils aware of ‘the converse view’, in other words promoting the opposing Coalition for Equal Marriage and other campaigns that support equal marriage for gay and straight couples.

Sections 406-7 of the Education Act 1996 forbids ‘the promotion of partisan political views in the teaching of any subject in the school’, and requires balanced treatment of political issues. The Catholic Education Service confirmed to PinkNews.co.uk that it had written to at least 359 Catholic state secondary schools in England and Wales last month 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.

In a written statement, Welsh Minister for Education and Skills Leighton Andrews sets out that the Education Act may have been broken, and that he has written to all Catholic secondary address this.

“This petition is only intended for signature by those aged 16 or over as the petition website makes clear. Head teachers were also asked to consider reading the letter out at school or class assemblies and arranging for its use in appropriate classes,” he wrote. “It is unfortunate that the original e-mail of 10 March did not make it clear that only persons aged 16 or over should sign the on-line petition, and I am pleased that the CES has now clarified this.”

In his letter to Catholic schools, Mr Andrews explains that “Whilst the petition itself is not directly related to a party political matter it does in my view relate to political matters generally as the petition is seeking to persuade people to lobby the Westminster Government to prevent a change in the law… I trust you will ensure that if your pupils have been made aware of this correspondence they will also be made aware of the converse view in order to give them a balanced perspective.”

BHA Faith Schools Campaigner Richy Thompson said: “We are pleased to see that the Welsh Government is in agreement with our own conclusions on this matter. This seems to us to be one of the most clear-cut examples of political indoctrination in schools that has ever been seen. We hope that the UK Government investigation reaches the same conclusion.”

However, the Welsh Government has concluded that the Catholic Education Service’s communications may not have broken the Equality Act. Mr Thompson said: “It seems to us to be likely that many schools will have stepped across the line and broken equalities law, as well as the law on political balance. The school in the original story, for example, described marriage and civil partnership as ‘unnatural’. Such behaviour is clearly going to leave LGBT pupils feeling victimised by their schools, trapped in a hostile environment. This is a very sad state of affairs.”

The English Education Secretary Michael Gove ordered a similar investigation after PinkNews.co.uk pleaded with him for action.