After a Stafford County high school student was suspended for dressing up in a banana costume and sprinting across a football field last week, some of his classmates protested the crackdown by wearing t-shirts with the slogan “Free Banana Man” emblazoned across them. When students began reporting that school officials told them to take off -- and in some instances confiscated -- the yellow shirts protesting 14-year-old Bryan Thompson’s suspension, the American Civil Liberties Union stepped in.

The ACLU told administrators at Colonial Forge High School Thursday that they must allow students to wear the t-shirts if they choose to, the Associated Press reported.

“It is well established law that students do not lose their free speech rights at the schoolhouse door,” ACLU of Virginia executive director Kent Willis said in a news release.

Rebecca Glenberg, legal director of the ACLU of Virginia, also sent a letter to the school principal, Karen Spillman.

“If this behavior took place in the classroom, and was disruptive, certainly there are some grounds for discipline,” Glenberg wrote. “But prohibiting students from merely wearing T-shirts expressing a particular opinion is unconstitutional.”

Valerie Cottongim, a school spokeswoman, said school officials were reviewing the letter but had no further comment.

Thomson has been suspended for 10 days and the principal has recommended he be suspended for the rest of the school year, according to the Free-Lance Star.

Thomson, who was previously suspended for having a cell phone in class and for setting up a Web site that officials said violated the school’s cyber bullying policy, is appealing this suspension.