Teenage girls inhabit a violent world, with four out of ten having been beaten up by another young person, a study of female aggression shows.

The two-year investigation found that most 13 to 16-year-old girls regarded fighting as an "ordinary, everyday occurrence" and that 98.5 per cent had witnessed violent incidents.

The study by researchers from the University of Glasgow, who interviewed 800 girls from a wide range of backgrounds, provides the most convincing evidence to date of rising levels of violence among young women in Britain.

The study, which was funded by the Economic and Social Research Council, found that 41 per cent of young girls had been the victim of violence at the hands of another young person.

Three out of every four of the girls questioned said they "frequently" witnessed violent incidents. Some of the girls admitted fighting.

The researchers classified 40 as being "routinely violent" while 80 of the girls described themselves as "violent" in responses to a questionnaire.

Dr Michele Burman, who led the research team, said: "One of the most surprising findings of the report was that a staggering 98.5 per cent of the girls had witnessed violent incidents of some form, usually a fight between other young people. More than 70 per cent said that they witnessed these kinds of incidents frequently and described them as an ordinary, everyday occurrence, whereas an adult is less likely to describe witnessing a fight as unremarkable."

But while violence was highly prevalent in the lives of the young girls, the idea that they operate in organised gangs was dismissed by the Glasgow researchers, who found that such activities were confined to boys. On the whole, girls preferred to try and talk their way out of disagreements.

Dr Burman said: "For the most part, violence and the carrying of weapons is not deemed to be cool and none of the girls reported being members of gangs.

"The majority of young girls pride themselves on being able to stick up for themselves without having to resort to violence."

Prison reform groups have noted that the number of women jailed for violence is a tiny fraction of the overall prison population and that many of the offences are linked to drug addiction.

At Britain's first conference on violence in the lives of young women, which took place in Scotland last Friday, teenage girls said they lived in fear of their peers.

Louise, a 16-year-old from Glasgow, said: "There are a lot of girls who hang about the streets in gangs looking for trouble. It's frightening walking past them on your own because they shout abuse and call you names, trying to wind you up. If you shout back at them it's likely they will hit you.

"For a while there was a gang of girls waiting for me and my friends to get off the bus every day after school and in the end I had to get my dad to collect me each afternoon."

Her friend Claire, 15, said: "We had to stop hanging around outside at nights because we were always getting chased by the girls. Often they would have metal poles or bottles. Once one of my friends was even threatened with a knife held up to her throat."