Single-sex schools "have a duty to promote equality" by adapting their premises and policies to welcome transgender pupils, a teaching union has heard.

Staff at girls' and boys' schools across the country reported how practical steps were being taken to modify changing facilities and uniforms to cater for trans pupils - while other schools are languishing behind in how to respond to the issue.

Schools have also been addressing negative or unhelpful attitudes, particularly among older staff who initially dismissed the trans process as a "fad".

Graham Easterlow, a drama teacher at a boys' special school, said a 17-year-old pupil with autism was given every support when she identified as female.

Speaking at the Association of Teachers and Lecturers (ATL) conference in Liverpool, Mr Easterlow said: "There was no flag-waving, there wasn't a great big protest or 'this is me!', it was very matter-of-fact.

"I think we have to approach it in that way, it's a natural process for people and not a badge-wearing exercise.

"The pupil was absolutely aware. She was extremely clear and knew exactly how she wanted to identify.

"The challenge came when we realised that the school was facing an issue for the first time and there was no precedent. There was no process to support that particular coming out.

"That's the difficulty. Schools are ill-prepared. And there is a blind spot on that particular issue and it's very, very clear that it's a blind spot."

He said teachers at his school in Yorkshire were briefed on how to deal with questions from any pupils about the trans process, but said everything was done "with very little fuss".

Asked about the initial reaction of some older staff, Mr Easterlow said some responded by saying: "It's all just a fad, it's not real, why are we pandering to this fad?"

He said: "There's a whole load of things around what our duty is to support trans equality and it's not just about particular races or sexism in the sense of male and binary gender.

"We have a duty to promote equality.

"I would like to see every school's equality drive being to look at gender prejudice."

He said he felt it more likely that transgender pupils struggled to come out at single-sex schools, but said tackling the issue was a universal one.

ATL members passed a motion to campaign for funding and provide support for young people exploring identity.

A Department for Education spokesman said: "Every child should feel able to reach their full potential and we know there are thousands of brilliant teachers creating supportive and inclusive environments for their pupils. We already provide advice to help schools understand how the Equality Act affects them, including specific guidance on trans issues.

"We are also investing £3 million in projects to help schools learn how to better deal with homophobic, biphobic and transphobic bullying. Sex education is compulsory in all maintained secondary schools - we are clear that it should be relevant to all pupils, and sensitive to their needs. "