The world's biggest investigation into the effects of mobile phones on the developing brains of children has been commissioned by the Department of Health.
Scientists have launched the Study of Cognition, Adolescents and Mobile Phones (Scamp) will focus on mental functions such as memory and attention which continue to develop into the teenage years.
About 2,500 school children will be tested at age 11 and 12 and undergo a further assessment two years later. Most children start to own a mobile phone at around 11 or 12.
Invitations have been sent out to more than 160 secondary schools in the outer London area to enrol pupils into the study.