They decorate their bedrooms in pink. They want to be beauty therapists when they grow up. They think babies are “soooo cute”.

But they spend their spare time lurking outside supermarkets, taking drugs and getting into fights.

Girls make up about 20 per cent of pupils who are permanently excluded from school in England and Wales. But, says Anna Conolly of the Institute of Education in London, any discussion about excluded pupils tends to focus on boys.

Dr Conolly interviewed 31 girls aged 12-16 in the Midlands and the South East. All had been excluded from school for bad behaviour or truanting and were now attending pupil referral units.

She found that most came from impoverished families. “The starkness of many of the rooms... served to highlight their lack of material possessions,” Dr Conolly said. “No concession was made in any of the rooms to a study area for doing homework.”

Space restrictions at home meant most of the girls spent their leisure time “hanging out” in public spaces.

“I go to Tesco’s about five times a night,” said teenager Jenni, “because it’s something to do.”

When asked what they do there, Beany, one interviewee, said: “Just sit there and do nothing, really. Sit there and smoke and drink... and steal loads of alcohol and get drunk.”

Teenager Shola said: “We just sit around in the tower blocks, smoking weed, making trouble, stealing from pizza men and stuff like that.”

Shola insisted her role in these activities was as prominent as that of her male friends: she did anything the boys would do.

Hanging out in the dark, in areas with poor housing and high unemployment, required them to be tough, so girls were as likely to end up in physical fights as boys. One interviewee described how two girls bit, kicked and dug at each other’s eyes during a fight over a comb.

“Fighting... appeared to be a visual demonstration to others that they were prepared to stand up for themselves and not be messed with,” said Dr Conolly. “To be seen in any way other than tough and able to take care of themselves would have left the young women weak and open to attack.”

But while the girls were keen to be seen as tough and streetwise, they also had an ultra-girly side. Many wanted to be beauty therapists. Others decorated their bedrooms with Playboy Bunnies, photos of small children, and, in one case, a pink television.

Dr Conolly described their interest in babies and young children as “almost idolisation”. Holding up a photo of a baby, teenager Gemma said: “She’s gorgeous, isn’t she? I love her to pieces. She’s soooo cute.”

Ultra-tough Kandice condemned a friend who smoked while pregnant. “It’s fucking harsh on the baby,” she said. “I wouldn’t, if I was pregnant.”

Dr Conolly believed this interest in babies, mothering and girliness was a vital counterpoint to the teenagers’ streetwise toughness.

“By presenting themselves as hyper-feminine in this manner, the excluded young women could easily fend off any criticism that might be engendered by acting in a laddish manner,” she said.

Anna Conolly will give a presentation at the Institute of Education in London on March 10.

20 - Percentage of pupils expelled from school who are girls.