Maths teacher Joshua Sutcliffe, 27, was suspended after the parents of a girl who identifies as a boy complained that he had been a victim of “misgendering”. 

Mr Sutcliffe had caused offence by praising the child and a girl for working hard, saying: “Well done girls.” 

Backing him yesterday, the Christian Legal Centre said schools had become a major battleground in the transgender ideology with a “flood of cases” where teachers are punished or fear punishment for failing to toe the line. 

Mr Sutcliffe apologised and thought nothing more about it when the pupil became angry. 

But at a parent-teacher meeting about six weeks later a complaint was made. 

Last month he was suspended at the state secondary school in Oxfordshire and had to spend all his time in isolation in the staff room, unable to discuss the case with his fellow teachers. 

After a week-long investigation, the school found Mr Sutcliffe to have “misgendered” the pupil, “demonstrating discriminatory behaviours” and contravening the school’s equality policy. 

Mr Sutcliffe, a pastor at an evangelical church in Oxford, had run a Bible club at the school attended by up to 100 pupils. 

But the legal centre which is backing Mr Sutcliffe said that after 18 months this was shut down while an “LGBT mindfulness” club continued to run. 

After some media reports the teacher faced investigations for breach of confidence and bringing the school into disrepute. 

He has worked at the school for more than two years, teaching 11 to 18-year-olds, achieving “excellent” results. 

The legal centre said the teacher had written to the headmaster accusing the school of making it impossible for him to continue working there. 

Mr Sutcliffe wrote: “As a Christian, I do not share your belief in the ideology of transgenderism. 

“Implementation of these ideas is detrimental to the welfare of children, which I believe should be a paramount consideration. 

“However, as a professional, I was always careful not to breach my employer’s policies so long as I was not forced to act contrary to my conscience.” 

He said he was more than willing to answer all the allegations. 

“However, I intend to do so before an independent tribunal, not before yourselves acting as a judge and jury. I regret that our relations have reached this point, but I feel I have no choice but to bring legal proceedings against you without further notice.” 

The chief executive of the legal centre, Andrea Williams, said that it is getting 250 inquiries a year from people in all walks of life about sexuality allegations. 

“If we collude in the transgender delusion we do not serve our children well, we harm them,” she added. 

The school could not be reached for comment yesterday but has stated that it would not be appropriate to comment on confidential staff disciplinary matters.