Figures have revealed the ages of the youngest children to be referred for drug and alcohol treatment in Portsmouth and Hampshire.
In the city, the youngest child referred by the city council for specialist treatment was 15, while in Hampshire it was 12.
It comes as freedom of information requests revealed children aged as young as four were referred for specialist treatment by education and children’s services in South Ayrshire.
Treatment experts said the most common reason for children to come into contact with drugs and alcohol is through their parents and preventative work is key to heading off misuse among youngsters.
The government defended the old and new curriculum, adding that all pupils should be taught about how drugs and other substances can be harmful to the body.
Elsewhere, eight-year-olds had been referred to services in Waltham Forest and East Ayrshire, while nine-year-olds had been referred in Herefordshire, Liverpool, Oxfordshire, Rutland, the Scottish Borders and West Berkshire. Authorities in Bury, Calderdale, Halton, Hull, Monmouthshire and Rochdale had seen 10-year-olds referred.
A referral can mean the child is vulnerable to drug and alcohol misuse through exposure from a parent or other relative, as was the case with the four year old in South Ayrshire, or could have started abusing substances themselves.
Some 366 children aged 12 or under were referred for treatment in 2012/13 in England, according to the most recent figures from Public Health England, compared with 433 in 2011/12.
More than half of under-13s – 59 per cent – received treatment for cannabis misuse, while a third were treated for alcohol misuse. A small number abused solvents.
Children are most commonly referred for treatment by education providers or youth offending teams.