The heads of the 34 Sydney Anglican schools have written an Open Letter to MPs, calling on Parliament to enshrine a positive right to religious freedom which at the moment is covered by anti-discrimination exemptions which allow schools to main their Christian ethos and mission.

"As Principals and Heads of Anglican Schools in Greater Sydney and the Illawarra we write this public letter to all members of the Parliament of Australia." the letter begins. "There has been quite some discussion recently about the rights of faith-based schools and their current exemptions under federal anti-discrimination legislation. The debate has been polemicised as the right to expel gay students, with little evidence that this occurs, and the right to dismiss gay staff members, again with little evidence that this occurs."

The letter says that the issue at hand for faith-based schools is the right to employ staff who support the ethos of the school.

"Some schools require evidence of an active faith that is consistent with the philosophy and ethos of the school. In other schools, there is a preference for employment of active adherents of the faith, but other staff, who may not personally identify with the faith, are still expected to support the overarching mission and ethos of the school. This is not inconsistent with the practice of most employers and their corporate goals, let alone political parties."

The letter, which was given to the Prime Minister and Opposition Leader, was also sent to every member of the Lower House and every Senator.

"It is overly simplistic to state that a teacher merely delivers academic content in the classroom. This ignores the powerful mentor and exemplar role all teachers play, and are expected to play, in the education of young people. Therefore, it is essential that a teacher supports the values, ethos and mission of the school as much as he or she can. It is not appropriate, for example, for a teacher to undermine or denigrate the beliefs and teachings of an employing school. This is a reasonable expectation not only of the employing school but also of many parents and families who have chosen the school for their children's education."

Referring to submissions before the Ruddock inquiry, the heads stated that "There is no effective protection under Australian law that guarantees religious freedom for both belief and action. This is strange given that it is enshrined in the United Nations' International Covenant on Civil and Political Rights, which Australia has formally ratified. The current exemptions, however clumsy, in the Sex Discrimination Act 1984 are really the only significant legal protections available to schools to maintain their ethos and values with regard to core issues of faith. A more general positive right would be far better, but until such time as religious freedom is codified in legislation, the exemptions should remain."

The letter was signed by all Heads, from those at North Shore schools such as Shore and Barker to the Sydney Anglican Schools Corporation Schools in new areas such as Oran Park.

In his Presidential Address this month, Archbishop Davies spoke directly about the misrepresentations of the Ruddock Report and selective leaking in the media.

"Let’s be very clear. Anglican schools in Sydney do not expel students for being gay. It is an absurd proposition and it is certainly not something we asked for in our submission to the Ruddock Review. We would gladly support any amendment to the Sex Discrimination Act 1984 which would clarify this. This issue was nothing more than a beat up and smoke screen to discredit the Ruddock Report and obscure the real issues." he said.

"What we have asked for is simply this: freedom of religion. It goes to the very heart of religious freedom that religious organisations should be able to operate according to their religious ethos. Anglican schools, if they are going to remain Anglican, must be able to employ staff who support the Christian values of the school."

The Head of St Andrew's Cathedral School, Dr John Collier, said "It is a significant moment when my fellow school Heads feel strongly enough to write an open letter to MPs. Our joint concerns go to the heart of school ethos and mission.”

Dr Tim Wright, Head of Shore School, told the ABC that the letter speaks for itself.

"I can tell you there hasn't been a gay student expelled from an Anglican school in my memory and there hasn't been a gay staff member sacked from an Anglican school in my memory. In fact generally speaking, at interview, the question we ask is - Are you able to support the Christian ethos of the School?  I would imagine if you are applying to work for the Greens, (then) you are asked about your views on climate change and they don't hire people who don’t accept that argument. So this is an ethos issue."

"I think the first thing that the schools are really on about -  at least in the Anglican Diocese of  Sydney - is the person of Jesus Christ and His teachings and how does that work out in terms of human flourishing?"

Dr Wright said it was difficult to have a civilised debate on the issue amid sloganeering.

"We use the term polemicised earlier in the letter because we think that there's been actually been quite a deliberate attempt to sink the central thrust of what I believe is the Ruddock review, having been part of a panel that presented it to it, which is to actually enshrine in Australian law a right to religious freedom. That's what we want."

The Ruddock report has yet to be officially released.