The head teacher of a top Bradford school today pleaded with parents to crack down on teenage sex, drug use and under-age drinking.

Linda Warrington, head of The Girls Grammar School, Bradford, said she was shocked at the explosion in youngsters drinking in pubs, taking drugs and sleeping around.

And she told more than 200 head teachers its was parents who must take responsibility for their youngsters' actions.Speaking today as president of the Girls' Schools Association at its annual conference in Newport, Wales, she said: "We cannot hold our hands up in horror and ignore what is happening.

"I can't be the only one to be horrified that it has become the norm for 14 and 15 year-olds to spend their free time drinking in pubs. Under age sex is considered quite acceptable by many as is experimentation with drugs."

But she said that parents were too frightened to say 'no' in case it made them unpopular. They feared rebellion and felt it was better for their children to be happy, she claimed. "Some parents do not want to risk a confrontation and so they let them do almost anything," she said. "They often take the easy path and leave it to the schools to instil discipline."

And she accused landlords of 'aiding and abetting' underage drinking by serving alcopops and the like to young drinkers.

Speaking to the Telegraph & Argus today, Mrs Warrington said some pupils were easily influenced by TV soaps and movies.

"There is a general concern about the increased social pressures that there are on our pupils at this time," she said.

"They're being led to believe that they're young adults all the time and so mimic adult behaviour, but as teenagers they often don't have the emotional maturity to cope.

"The film industry shows images of how other young people behave and they think that this is normal. There are a couple of soaps on the TV at the moment where teenagers have just had babies, and although I suppose they are trying to portray the fact that it isn't all wonderful or easy, it still sends out the message that it's normal."

Mrs Warrington, pictured, said she feared she was overstepping the mark when telling parents they should not let their 13 and 14-year-old daughters go to pubs and clubs.

But they had thanked her saying, "Now I can say 'no' because I can say you said so".

But society saw young sex as the norm, she said. A leaflet aimed at 14-16 year olds had been produced by the Brook Street advisory clinic suggesting ways of enjoying sex.

She feared new dangers being created through chatlines and the internet and said that schools and parents should be vigilant and share information about preventative software.

"Parents need our support, but we also need theirs," she said. "I am saying that without self-discipline and without a sense of responsibility the future of society is indeed bleak."