A committee of MPs has heard that a Christian teacher in Scotland claims he was forced to teach about same-sex marriage against his wishes – and the stress contributed to a breakdown.

Samuel Webster, an in-house solicitor at the Christian Institute; the same organisation which earlier this week criticised 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 – has given a submission to the Public Bill Committee of the House of Commons.

Since last month’s Commons vote, the committee has been scrutinising the Marriage (Same Sex Couples) Bill for England and Wales.

In a submission to the committee, Samuel Webster, revealed that he had dealt with two cases – one involving a London primary school teacher in 2009 – the other involving a Scottish teacher, referred to as Mr X, in 2012.

In the second case, Mr X, who teaches philosophy in a state secondary school in Scotland claims he was required by his school to teach about same-sex marriage as part Religious and Moral Education (RME) in a way which he could not in good conscience do.

Mr Webster spoke of the teacher having “no problem” informing his students about sexuality, and homosexuality, but that “he couldn’t in good conscience state that opposite and same-sex relationships are the same.”

It is claimed Mr X was told by his head of department that heterosexual marriage is just an “Old Testament concept.”

When Mr X replied that this was not correct, his superior is said to have become angry when Mr X said that he had a problem with saying same-sex marriage is the same as heterosexual marriage.

During a departmental meeting, his superior produced an article from the Times Education Supplement about equal marriage and said “if you have a problem go and see the boss”.

Mr Webster said: “When Mr X spoke to the head teacher, he said that he had a problem because as a Christian he goes by what the Bible says and teaching about same-sex marriage would mean having to say something which goes against his beliefs.”

The head teacher subsequently told Mr X that he would have to teach the relationships course “without exemptions or safeguards” and not state his own views.

Mr Webster added: “This incident contributed to Mr X having a breakdown and being signed off work for several months with stress. Happily, he is shortly returning to school where matters now appear to be resolved, although not without personal cost to Mr X. I understand that his union has been supportive.”