A leading public school headmistress has warned that social networking sites and celebrities are creating a generation of "mean girls".
In a fierce attack, Helen Wright said sites such as Facebook encouraged teenagers to believe "bitching is good".
"They're far more used to defriending friends online rather than befriending them in reality. If it's possible in just a moment to defriend someone or unfriend them on Facebook, then people say, "Why can't I do that in real life?" the Daily Mail quoted her as saying.
"We are in real danger of cultivating a generation of "mean girls''," she said.
The headmistress of St Mary's Calne in Wiltshire also criticised a lack of positive role models for young women, saying high-profile female friendships seem to be based on "bitchiness, meanness, cruelty and criticising what someone's wearing and how they look".
"Many young women mistakenly se women like Paris Hilton and her latest BFF [best friend forever] and the cast of The Only Way Is Essex as relevant role models and seek to emulate their behaviour," she said.
Party-loving Paris Hilton and TV personality Nicole Richie had a public falling-out in 2005, after which the two refused to speak to each other for more than a year.
It was rumoured Richie had caused the rift by showing friends a sex tape featuring the heiress, but she denied this.
In other rows, Gwyneth Paltrow aimed barbed comments at Madonna as they competed for the services of a female personal trainer, while Geri Halliwell was the one 'Spice Girl' not invited to the Beckhams' wedding after her clash with Victoria.
Former pupils of 29,694-pound-a-year St Mary's include David Cameron's sister Clare andJade Jagger, who was expelled for sneaking out to meet a boyfriend.
Wright, former president of the Girls' Schools Association and Tatler magazine's Best Head of a Public School in 2010-11, also criticised TV talent competitions.
"Female judges in The X Factor or Strictly are always pitted against each other.
"There's always a subtext of meanness or nastiness. Young girls take this on face value and believe this is how they should act," she said.
She blamed the influence of the Eighties and Nineties 'ladette culture' on today's girls.
"If you look back to when they were born, at that early stage of life, you've got that hard-drinking, hard-partying, sexually aware culture of women.
"You imagine being a girl born at that time, going all the way through the first decade of the millennium - what messages have you picked up about how women are? It's a total lack of self-respect and a total lack of respect for others," she added.