“This is the most humiliating moment of my career,” the headmaster of Shore, Dr Tim Wright, told Guardian Australia. “I love the school. I love the boys. I feel I have let them down. I am sorry.”

Wright was one of 34 headmasters and headmistresses of Anglican schools in Sydney who signed, at the direction of the local church, an open letter calling for fresh legal protections for religious freedom. The letter cited – and did not step back from – rights religious schools already have to expel gay students and dismiss gay staff members.

Wright helped draft the letter. He now calls it an inept communication. “I thought we had put aside the issue of discriminating against gay kids and gay teachers.”

But the minute the letter appeared he had parents and old boys on the line asking: “What on earth are you trying to say? What is this all about?”

The Establishment is appalled. Old boys, old girls and parents with kids at a slew of the most prestigious – and expensive – schools in Australia are demanding to know what’s going on. In the face of this uproar, the heads of Barker and Abbotsleigh have both apologised for signing the letter.

Megan Krimmer of Abbotsleigh said on Tuesday: “Reflecting deeply on the feedback and issues raised, the incongruity between saying Abbotsleigh does not discriminate, and supporting highly discriminatory legislation, albeit temporarily, has become clear.”

Wright adds his name to that list. He says he is devastated by the hurt that has been caused by the letter. “It is just awful.” Read more via the Guardian