A Tennessee student claims his principal assaulted him for wearing a t-shirt in support of a school gay-straight alliance.

Chris Sigler, 17, a student at Sequoyah High School, wore a home-made shirt which read ‘GSA: We’ve got your back’ last Tuesday.

He says a teacher told him not to wear it in future but, knowing his rights, he wore it again the following Friday.

Sigler claims that principal Maurice Moser, who previously threatened to punish students for publicising a proposed gay-straight alliance, grabbed his arm, shoved him and chest-bumped him repeatedly while asking “Who’s the big man now?”

Moser had ordered all students to leave the classroom but Sigler’s sister Jessica, who refused to leave, witnessed the incident, the siblings said.

Sigler’s mother reported that when she arrived at the school that afternoon, she saw Moser leaning over her son and shouting in his face.

The family filed a report about the incident with the Monroe County Sheriff’s Department.

Sigler said: “All I want is to have a GSA at my school to help stop the bullying against gays and lesbians and their friends who support them.

“The shirt was a way to use my voice and show my support for the club. The way I was treated shows even more why we need a GSA here.”

He is being supported by the American Civil Liberties Union of Tennessee, which has written to the school to demand that students’ free speech rights be protected.