Kluge originally called pupils by their surnames (David McNew/Getty Images)

Students have reacted angrily after an anti same-sex marriage leaflet was left in their school library.

The leaflet listed different reasons why people should oppose equality.

Staff and students rejected the leaflet after finding it at the grammar school in Belfast, Northern Ireland.

The leaflet, entitled “10 reasons why homosexual ‘marriage’ is harmful and must be opposed”, was found in the school’s library.

It appears to have made by TFP Student Action which calls itself a “nationwide network of young Americans dedicated to defending and promoting moral values on college campuses and beyond”.

The reasons given for opposing marriage equality included, “it is not marriage”, “it violates natural law”, “it always denies a child either a father or a mother” and “it offends God”.

Northern Ireland is the only part of the UK not to allow same-sex marriage.

Students have written online at feeling offended and uncomfortable by the leaflet, which was in a pile of about 20 others available in the school.

One student, in a same-sex relationship themselves, said: “The leaflet is nothing short of a cheap propaganda leaflet that has been distributed to intimidate and/or to cause offence to pupils who engage in same-sex relationships.

“I personally am a pupil of the school, I am in a same-sex relationship and at no point has this been an issue with other pupils, however I fear that leaflets like this may entice homophobic behaviour that may lead to me being bullied or others in the future being bullied.”

Staff have rejected the leaflet as well as students, saying they don’t know how it got there.

The school told the Belfast Telegraph they did not sanction the leaflet, saying: “We became aware at 11am on February 21 that an unauthorised leaflet had been placed in the senior library of the college.

“The school immediately investigated the matter and while we are aware of some of the content of the document, we have been unable to find the original copy.

“The principal and board of governors did not sanction the placing of this leaflet in the school library.”

In Australia, a school was in hot water after their bus driver distributed anti-marriage equality leaflets disguised as Christmas presents to students.