Children as young as 12 treated for addictions at The Priory

The facility, which is famous for its celebrity patients, said the specialist unit was set up after a mounting demand from worried parents. It also treats children with eating disorders and behavioural issues such as an obsession with video games.

"The age of experimentation is dropping every year and children are experimenting with alcohol and drugs at a much younger age," Karen Croft, a spokeswoman for the hospital said.

"Unfortunately they are more vulnerable as the region of the brain that governs impulse and motivation is not fully formed. So the addictive action of the drug may occur more rapidly and possibly with greater permanence," she told The Independent.

A report by Alcohol Concern last month found that girls aged between 11 and 13 are drinking 83 per cent more units of alcohol than they were in 2000. Boys of the same age are now consuming an average of 12 units a week, a rise of 43 per cent.

Ms Croft added that they were also seeing more cases of computer and gaming addictions among youngsters and parents should look out for warning signs.

"Parents need to ask themselves some quite basic questions," she said.

"Is it interfering with the child's life? Are computers interfering with their school work and family relationships? Do they have good peer relationships?"

Children can be referred to the hospital by their GP and they accept both NHS and private cases.