Campaigners have condemned the arrest and expulsion of a lesbian high school pupil for having a same-sex relationship with a younger student.

Kaitlyn Hunt faces felony charges after the mother of her girlfriend, aged 14, notified police of the relationship as soon as she turned 18.

She has been charged with two counts of lewd and lascivious battery of a child 12 to 16 years of age and has been expelled from Sebastian River High School, in the town of Sebastian, Florida.

The American Civil Liberties Union (ACLU) says that no one can seriously maintain that Kaitlyn’s behaviour was predatory.

Despite a worldwide social media campaign to get the charges dropped, Florida State Attorney Bruce Colton has so far refused.

Prosecutors have offered a plea deal if she pleads guilty to lesser charges of child abuse, and that would allow her to avoid registering as a sex offender.

Mr Colton said he would recommend two years of house arrest followed by a year’s probation.

A Facebook page called “Stop the Hate Free Kate” now has nearly 45,000 members.

“It’s horrible. For my daughter’s sexual preferences, she’s getting two felony charges. It could possibly ruin her future,” Steve Hunt, the father of Kaitlyn, told the Associated Press in a phone interview this week.

In an usual twist, Kaitlyn came across another 18-year-old female student at the school she was forced to transfer to, also having sex with an underage girl. She was the only witness but notified authorities what she saw in the girl’s bathroom.

While an arrest was made, the 18-year-old girl was set free because the younger girl’s parents did not complain.