The Scottish Catholic Education Service has said the introduction of marriage equality would stop state-funded Catholic schools teaching children the faith’s views that marriage can only be between a man and a woman.

The director said it was ‘ironic’ for First Minister Alex Salmond to praise Catholic schools for giving students moral direction while considering implementing marriage equality contrary to the Church’s views.

The Scottish government has said it “tends toward” the introduction of marriage equality, a move similarly supported by the leaders of all the country’s major opposition parties but opposed by the Catholic Church though ministers have said it would not be forced to solemnise gay unions.

Scotland’s most senior Catholic, Cardinal Keith O’Brien described such equality as a “grotesque subversion of a universally accepted human right” and said allowing it to take place would be similar to allowing other citizens to keep slaves.

Michael McGrath, director of the Scottish Catholic Education Service for Scotland’s 373 Catholic schools, told The Herald: “Despite the First Minster’s rhetoric of support for faith communities and for denominational schools, this Government’s actions appear to be designed to undermine both.

“While the First Minister has expressed his admiration of Catholic schools for their moral teaching, it is ironic that this legislation attempts to set aside one major item of Christian moral teaching – the sanctity of marriage as a covenant between husband and wife.

“This understanding of the sanctity of marriage is divinely ordained in Church doctrine and underpins the teaching of marriage in Catholic schools across the world.”

Mr McGrath said a response to the Scottish government’s 2011 public consultation on marriage equality had highlighted its fears that schools would no longer be able to teach children the Catholic view of marriage.

He said: “The commission, in its response to the consultation, has expressed significant concern that, if such legislation were enacted, it would become impossible for teachers in Catholic schools to teach conscientiously, according to the doctrines of the Catholic Church, as parents expect them to do.

“While the right of teachers in faith schools to promote the doctrines of a school’s denominational body is recognised in the Equality Act 2010, the commission is concerned that teachers would be compelled to teach according to the policies of their employers – local councils.

“Such policies would certainly require the teaching of marriage as a legal contract, rather than any doctrinal understanding of marriage as a Sacrament.”

The results of the Scottish government’s consultation on marriage equality will be released later this year. It has said it has so far formed no “final views”.

The Catholic Education Service in England and Wales is now the subject of a government investigation after PinkNews.co.uk’s discovery last week that it had written to between 359 and 389 Catholic secondary schools asking them to promote the Coalition for Marriage anti-equality petition.

Michael Gove ordered the investigation this weekend following suggestions that it may have been illegal to teach children an unbalanced view on the issue, which is currently the subject of intense political debate, and to promote among them a petition whose organisers have told PinkNews.co.uk it is political, not religious, document.

A spokesman for Mr Gove told PinkNews.co.uk: “Schools have a responsibility under law to ensure children are insulated from political activity and campaigning in the classroom.

He added: “While faith schools, rightly, have the freedom to teach about sexual relations and marriage in the context of their own religion, that should not extend to political campaigning.”

“Officials are looking into this as the Education Secretary and other ministers are anxious to establish the full facts of this case and will be meeting representatives of the Catholic Education Service shortly.”