When drama teacher Lisa Garside told her head she intended to return to work as a man after the summer holidays, the school was faced with a problem: how to handle the situation in the best possible way.

“We informed the local education authority and we tried to search for precedents but we couldn’t find any. We even trawled the Internet but found nothing,” said David Hudson, head of King James’ School in Knaresborough, North Yorkshire.

“For the legal position I searched through a law book myself and read up on sexual discrimination and equal opportunities, and it was clear there were no grounds for anybody to have a problem with this.”

Having worked things out the hard way, Dr Hudson now hopes the experience at his school will be an inspiration to any others facing the same unusual situation.

He added: “It is important not just to talk about principles, but to actually live them. Too often just lip service is paid to equal opportunities. With this issue we have had a chance to practise what we preach.”

The school is unswerving in its support for Miss Garside, 36, who will return in September as Mike. She has taught at the 1,500-pupil school for 14 years, and was praised in a recent OFSTED inspection. She told the school of her intentions earlier this term, as the hormone therapy she is having will bring changes which will be impossible to disguise.

Last week, a letter was sent to all staff and parents to avoid rumour and gossip.

“I sent letters to the parents and we could see the children opening them on the school bus and the older pupils explaining to the younger ones what it meant,” said Dr Hudson.

Reactions were supportive, with just one complaint from a parent and one insensitive jibe from a pupil. There has also been an increase in enquiries from parents wanting to send children to the school, saying they approved of the way the situation was handled.

Miss Garside decided four years ago not to do PE cover, and had used the visitors’ toilet facilities, which are self-contained.

She said: “I thought it was important that I was open and honest about this. I cannot go back, I have to move on. I have been considering changing gender for several years. You think you are going to be thrown out on your ear. But that hasn’t happened.”

She intended to discuss the issue with the two groups she teaches from Years 10 and 12 as well as her Year 11 tutor group.

“I will be keeping it brief, and explaining things will be different for all of us. I am not expecting their understanding because I know it is very difficult for them to understand. Their support, though, will be welcomed. ”

Dr Hudson said the only problem had been caused by camera crews and photographers demanding interviews. An offer from a tabloid Sunday newspaper to buy the story was rejected and the rest were stalled until a press officer arrived from County Hall.

Miss Garside admitted to being a little apprehensive about returning in September. “On the first day I will be very nervous. there will be slips, people will still go back to my original name, but we will get through it,” she said.