A Christian teacher and pastor suspended for "misgendering" a transgender student is suing his school for religious discrimination and said his case reflects "an increasing trend of Christians being marginalized in the public square."

The controversy began when Joshua Sutcliffe, 27, who teaches math at an Oxfordshire secondary school and pastors an evangelical church, said, "Well done girls" to the teenager, who was born a female but identifies as a male, and a friend when he spotted them studying.

He apologized when corrected by the student, but six weeks later he was suspended from teaching and faced a disciplinary hearing after the pupil's mother lodged a complaint.

Following the week-long investigation, the school found Sutcliffe to have "misgendered" the pupil, "demonstrating discriminatory behaviors" and "contravened the school's equality policy."

Now, Sutcliffe is taking the school in Oxfordshire to an employment tribunal, claiming he has been victimized for his Christian beliefs - with his rights "systematically and maliciously" breached, according to the Mail Online.

Sutcliffe told reporters he was "distraught" by what he referred to as "political correctness gone mad," explaining that he had no official instructions about how to address the student. However, as a Christian, the teacher said he avoided using male pronouns such as "he" and "him" when referring to the student.

"While the suggestion that gender is fluid conflicts sharply with my Christian beliefs, I recognize my responsibility as a teacher and Christian to treat each of my pupils with respect," he said. "I have balanced these factors by using the pupil's chosen name, and although I did not intentionally refer to the pupil as a 'girl,' I do not believe it is unreasonable to call someone a girl if they were born a girl."

"I said it was only one incident for which I had apologized, but he insisted the investigation would go ahead," he continued. "I had always tried to respect the pupil and keep a professional attitude as well as my integrity, but it seemed to me that the school was trying to force me to adhere to its liberal, Leftist agenda."

Sutcliffe said he assumed the investigation would be brief and he would soon be back in the classroom. However, he was questioned several times, and later received a letter telling him to attend a formal disciplinary hearing this Wednesday, attended by the head and three governors.

"'I have never been trained to deal with this sort of thing. I felt completely out of my depth and intimidated," he said.

"I have been shocked and saddened by the actions of the school, which, in my opinion, reflect an increasing trend of Christians being marginalized in the public square, and unpopular beliefs silenced," he added.

Andrea Williams, chief executive of the Christian Legal Centre which is supporting the teacher, said this case is just one of many where teachers are "finding themselves silenced or punished if they refuse to fall in line with the current sexual and gender ideology being imposed on our children in schools."

"We all know how much we change during our teenage years. It is vital that during those years we help our children to live in the biological sex they were born rather than encouraging them to change 'gender,'" she said.

"If we encourage them to change gender it is not kind and compassionate; it is cruel. What we need is a culture in our schools which gives emotional support to children through puberty without encouraging them to make life-long decisions against their natural born biological sex. If we collude in the transgender delusion we do not serve our children well, we harm them."

Sutcliffe has previously come under fire for his biblical view of gender and sexuality; several years ago, a voluntary Bible club he started during lunchtime was shut down after he answered a student's question on marriage by saying the Bible described it as being between a man and a woman.