Crack den art at the Tate

A body lies prone on a filthy mattress in the corner. A man slumps in a chair amid smashed furniture and graffiti-covered walls.

On the floor lies the detritus of crack cocaine use. A child aged about six sits in the corner, defensively clutching her knees to her chest.

This ghastly mock-up of an innercity crack den is art, and it will go on show at the Tate Modern next week. It was created by south London teenagers based on their experience of living in such conditions.

The children, all from extremely disadvantaged backgrounds, attend Kids Company, a Peckham-based youth project. Its director, Camila Batmanghelidjh, said that creating the artwork had given the children a sense of achievement and a chance to express themselves. She hopes the exhibition will provoke a public debate on the way childhood is being eroded.

One of the artists, Sammy, 17, was only four when his father died of a crack overdose. Sammy spent his childhood hanging out on an estate with the "pushers and crackheads" who had been his father's friends. He first smoked cannabis at eight, but avoided getting hooked on crack. At 14 he left home to live in a squat.

"I just want people to know what crack is like, what it does to your family," he said. "They turn like prostitutes, selling their bodies for money. I have seen people die. I've seen babies in crack houses, just sitting there on the bed. I want people to see what it's like for the babies."

Another of the artists, Nathan, 15, said: "I could show you houses I have been in where the first thing you see is needles, crack, guns, someone getting shagged in one room, people overdosing in the bathroom. It's mad."

The Shrinking Childhoods exhibition, which opens next Thursday, will be in temporary buildings representing-part of a council estate in Tate Modern's grounds. In each room, children will create scenes from their lives.

More than 300 children visit Kids Company each week, up to 90 per cent from broken homes with no father figure. Most have suffered physical, sexual or emotional abuse. Many have dropped out of school or been expelled.

Half have left home. Some are violent young offenders, others are vulnerable victims. Many have behavioural or mental health problems. The group receives 90 per cent of its funding from donations, including £50,000 from Evening Standard readers when it was chosen for our Christmas appeal.

Ms Batmanghelidjh said: "Every day we meet lone children who carry the burden of their own survival and live with worry for their carers' well-being. Government does not recognise the 'unparented' child. There are no funding structures or departments to meet their needs."

Police blame London's estimated 45,000 crack addicts for much of the mugging, theft and burglary in the capital.

The children's names have been changed at their request.